How do you convert Unix epoch time into real time in C#? (Epoch beginning 1/1/1970)
UPDATE 2020
You can do this with DateTimeOffset
DateTimeOffset dateTimeOffset = DateTimeOffset.FromUnixTimeSeconds(epochSeconds);
DateTimeOffset dateTimeOffset2 = DateTimeOffset.FromUnixTimeMilliseconds(epochMilliseconds);
And if you need the DateTime object instead of DateTimeOffset, then you can call the DateTime property
DateTime dateTime = dateTimeOffset.DateTime;
Original answer
I presume that you mean Unix time, which is defined as the number of seconds since midnight (UTC) on 1st January 1970.
private static readonly DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
public static DateTime FromUnixTime(long unixTime)
{
return epoch.AddSeconds(unixTime);
}
The latest version of .Net (v4.6) just added built-in support for Unix time conversions. That includes both to and from Unix time represented by either seconds or milliseconds.
Unix time in seconds to DateTimeOffset:
DateTimeOffset dateTimeOffset = DateTimeOffset.FromUnixTimeSeconds(1000);
DateTimeOffset to Unix time in seconds:
long unixTimeStampInSeconds = dateTimeOffset.ToUnixTimeSeconds();
Unix time in milliseconds to DateTimeOffset:
DateTimeOffset dateTimeOffset = DateTimeOffset.FromUnixTimeMilliseconds(1000000);
DateTimeOffset to Unix time in milliseconds:
long unixTimeStampInMilliseconds= dateTimeOffset.ToUnixTimeMilliseconds();
Note: These methods convert to and from DateTimeOffset. To get a DateTime representation simply use the DateTimeOffset.DateTime property:
DateTime dateTime = dateTimeOffset.UtcDateTime;
With all credit to LukeH, I've put together some extension methods for easy use:
public static DateTime FromUnixTime(this long unixTime)
{
var epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
return epoch.AddSeconds(unixTime);
}
public static long ToUnixTime(this DateTime date)
{
var epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
return Convert.ToInt64((date - epoch).TotalSeconds);
}
Note the comment below from CodesInChaos that the above FromUnixTime returns a DateTime with a Kind of Utc, which is fine, but the above ToUnixTime is much more suspect in that doesn't account for what kind of DateTime the given date is. To allow for date's Kind being either Utc or Local, use ToUniversalTime:
public static long ToUnixTime(this DateTime date)
{
var epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
return Convert.ToInt64((date.ToUniversalTime() - epoch).TotalSeconds);
}
ToUniversalTime will convert a Local (or Unspecified) DateTime to Utc.
if you dont want to create the epoch DateTime instance when moving from DateTime to epoch you can also do:
public static long ToUnixTime(this DateTime date)
{
return (date.ToUniversalTime().Ticks - 621355968000000000) / 10000000;
}
You actually want to AddMilliseconds(milliseconds), not seconds. Adding seconds will give you an out of range exception.
The Unix epoch is the number of seconds that have elapsed since January 1, 1970 at midnight UTC time minus the leap seconds. This means that at midnight of January 1, 1970, Unix time was 0. The Unix epoch is also called Unix time, POSIX time, or Unix timestamp.
With .Net Framework 4.6 or higher Use the method DateTimeOffset.ToUnixTimeMilliseconds() It returns the number of milliseconds that have elapsed since 1970-01-01T00:00:00.000Z.
var EPOCH = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();
It's well documented here DateTimeOffset.ToUnixTimeMilliseconds
To get the EPOCH with seconds only you may use
var Epoch = (int)(DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)).TotalSeconds;
and convert the Epoch to DateTime with the following method
private DateTime Epoch2UTCNow(int epoch)
{
return new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddSeconds(epoch);
}
But Since
On systems where the representation of Unix time is as a signed 32-bit number, the representation will end after 231 - 1 seconds which will happen at 3:14:08 on 19 January 2038 UTC. This is called the Year 2038 problem where the 32-bit signed Unix time will overflow.
I suggest to save it as long not int as EPOCH_2038_SAFE
long EPOCH_2038_SAFE =
(long)(DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)).TotalSeconds;
If you are looking for more, use the following with more ticks precision
long EPOCH = DateTime.UtcNow.Ticks - new DateTime(1970, 1, 1,0,0,0,0).Ticks;
If you want better performance you can use this version.
public const long UnixEpochTicks = 621355968000000000;
public const long TicksPerMillisecond = 10000;
public const long TicksPerSecond = TicksPerMillisecond * 1000;
//[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static DateTime FromUnixTimestamp(this long unixTime)
{
return new DateTime(UnixEpochTicks + unixTime * TicksPerSecond);
}
From a quick benchmark (BenchmarkDotNet) under net471 I get this number:
Method | Mean | Error | StdDev | Scaled |
-------------- |---------:|----------:|----------:|-------:|
LukeH | 5.897 ns | 0.0897 ns | 0.0795 ns | 1.00 |
MyCustom | 3.176 ns | 0.0573 ns | 0.0536 ns | 0.54 |
2x faster against LukeH's version (if the performance mater)
This is similar to how DateTime internally work.
// convert datetime to unix epoch seconds
public static long ToUnixTime(DateTime date)
{
var epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
return Convert.ToInt64((date.ToUniversalTime() - epoch).TotalSeconds);
}
Should use ToUniversalTime() for the DateTime object.
currently you can simply use
DateTimeOffset.UtcNow.ToUnixTimeMilliseconds()
it will be returned as a 64-bits long
I use following extension methods for epoch conversion
public static int GetEpochSeconds(this DateTime date)
{
TimeSpan t = DateTime.UtcNow - new DateTime(1970, 1, 1);
return (int)t.TotalSeconds;
}
public static DateTime FromEpochSeconds(this DateTime date, long EpochSeconds)
{
var epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
return epoch.AddSeconds(EpochSeconds);
}
Since .Net 4.6 and above please use
DateTimeOffset.Now.ToUnixTimeSeconds()
To not worry about using milliseconds or seconds just do:
public static DateTime _ToDateTime(this long unixEpochTime)
{
DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
var date = epoch.AddMilliseconds(unixEpochTime);
if (date.Year > 1972)
return date;
return epoch.AddSeconds(unixEpochTime);
}
If epoch time is in seconds then there is no way you can pass year 1972 adding milliseconds.
If you are not using 4.6, this may help Source: System.IdentityModel.Tokens
/// <summary>
/// DateTime as UTV for UnixEpoch
/// </summary>
public static readonly DateTime UnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
/// <summary>
/// Per JWT spec:
/// Gets the number of seconds from 1970-01-01T0:0:0Z as measured in UTC until the desired date/time.
/// </summary>
/// <param name="datetime">The DateTime to convert to seconds.</param>
/// <remarks>if dateTimeUtc less than UnixEpoch, return 0</remarks>
/// <returns>the number of seconds since Unix Epoch.</returns>
public static long GetIntDate(DateTime datetime)
{
DateTime dateTimeUtc = datetime;
if (datetime.Kind != DateTimeKind.Utc)
{
dateTimeUtc = datetime.ToUniversalTime();
}
if (dateTimeUtc.ToUniversalTime() <= UnixEpoch)
{
return 0;
}
return (long)(dateTimeUtc - UnixEpoch).TotalSeconds;
}
In case you need to convert a timeval struct (seconds, microseconds) containing UNIX time to DateTime without losing precision, this is how:
DateTime _epochTime = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
private DateTime UnixTimeToDateTime(Timeval unixTime)
{
return _epochTime.AddTicks(
unixTime.Seconds * TimeSpan.TicksPerSecond +
unixTime.Microseconds * TimeSpan.TicksPerMillisecond/1000);
}
Here is my solution:
public long GetTime()
{
DateTime dtCurTime = DateTime.Now.ToUniversalTime();
DateTime dtEpochStartTime = Convert.ToDateTime("1/1/1970 0:00:00 AM");
TimeSpan ts = dtCurTime.Subtract(dtEpochStartTime);
double epochtime;
epochtime = ((((((ts.Days * 24) + ts.Hours) * 60) + ts.Minutes) * 60) + ts.Seconds);
return Convert.ToInt64(epochtime);
}
Related
There is this example code, but then it starts talking about millisecond / nanosecond problems.
The same question is on MSDN, Seconds since the Unix epoch in C#.
This is what I've got so far:
public Double CreatedEpoch
{
get
{
DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, 0).ToLocalTime();
TimeSpan span = (this.Created.ToLocalTime() - epoch);
return span.TotalSeconds;
}
set
{
DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, 0).ToLocalTime();
this.Created = epoch.AddSeconds(value);
}
}
Here's what you need:
public static DateTime UnixTimeStampToDateTime( double unixTimeStamp )
{
// Unix timestamp is seconds past epoch
DateTime dateTime = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
dateTime = dateTime.AddSeconds( unixTimeStamp ).ToLocalTime();
return dateTime;
}
Or, for Java (which is different because the timestamp is in milliseconds, not seconds):
public static DateTime JavaTimeStampToDateTime( double javaTimeStamp )
{
// Java timestamp is milliseconds past epoch
DateTime dateTime = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
dateTime = dateTime.AddMilliseconds( javaTimeStamp ).ToLocalTime();
return dateTime;
}
The latest version of .NET (v4.6) has added built-in support for Unix time conversions. That includes both to and from Unix time represented by either seconds or milliseconds.
Unix time in seconds to UTC DateTimeOffset:
DateTimeOffset dateTimeOffset = DateTimeOffset.FromUnixTimeSeconds(1000);
DateTimeOffset to Unix time in seconds:
long unixTimeStampInSeconds = dateTimeOffset.ToUnixTimeSeconds();
Unix time in milliseconds to UTC DateTimeOffset:
DateTimeOffset dateTimeOffset = DateTimeOffset.FromUnixTimeMilliseconds(1000000);
DateTimeOffset to Unix time in milliseconds:
long unixTimeStampInMilliseconds = dateTimeOffset.ToUnixTimeMilliseconds();
Note: These methods convert to and from a UTC DateTimeOffset. To get a DateTime representation simply use the DateTimeOffset.UtcDateTime or DateTimeOffset.LocalDateTime properties:
DateTime dateTime = dateTimeOffset.UtcDateTime;
DateTime to UNIX timestamp:
public static double DateTimeToUnixTimestamp(DateTime dateTime)
{
return (TimeZoneInfo.ConvertTimeToUtc(dateTime) -
new DateTime(1970, 1, 1, 0, 0, 0, 0, System.DateTimeKind.Utc)).TotalSeconds;
}
From Wikipedia:
UTC does not change with a change of seasons, but local time or civil time may change if a time zone jurisdiction observes daylight saving time (summer time). For example, local time on the east coast of the United States is five hours behind UTC during winter, but four hours behind while daylight saving is observed there.
So this is my code:
TimeSpan span = (DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0,DateTimeKind.Utc));
double unixTime = span.TotalSeconds;
You can use DateTimeOffset.
For example. I have a DateTime object
var dateTime1 = DateTime.Now;
If I want to convert it to the Unix time stamps, it can be achieved as follows
var unixTimeSeconds = new DateTimeOffset(dateTime1).ToUnixTimeSeconds()
If you want convert unix timeStamp to normal DateTime, you can use this code piece:
var dateTime2 = DateTimeOffset.FromUnixTimeSeconds(unixTimeSeconds).LocalDateTime;
or
var dateTime2 = DateTimeOffset.FromUnixTimeSeconds(unixTimeSeconds).UtcDateTime;
For more information please visit this link :
DateTimeOffset.ToUnixTimeSeconds Method,
DateTimeOffset.FromUnixTimeSeconds
Be careful, if you need precision higher than milliseconds!
.NET (v4.6) methods (e.g. FromUnixTimeMilliseconds) don't provide this precision.
AddSeconds and AddMilliseconds also cut off the microseconds in the double.
These versions have high precision:
Unix -> DateTime
public static DateTime UnixTimestampToDateTime(double unixTime)
{
DateTime unixStart = new DateTime(1970, 1, 1, 0, 0, 0, 0, System.DateTimeKind.Utc);
long unixTimeStampInTicks = (long) (unixTime * TimeSpan.TicksPerSecond);
return new DateTime(unixStart.Ticks + unixTimeStampInTicks, System.DateTimeKind.Utc);
}
DateTime -> Unix
public static double DateTimeToUnixTimestamp(DateTime dateTime)
{
DateTime unixStart = new DateTime(1970, 1, 1, 0, 0, 0, 0, System.DateTimeKind.Utc);
long unixTimeStampInTicks = (dateTime.ToUniversalTime() - unixStart).Ticks;
return (double) unixTimeStampInTicks / TimeSpan.TicksPerSecond;
}
See IdentityModel.EpochTimeExtensions
public static class EpochTimeExtensions
{
/// <summary>
/// Converts the given date value to epoch time.
/// </summary>
public static long ToEpochTime(this DateTime dateTime)
{
var date = dateTime.ToUniversalTime();
var ticks = date.Ticks - new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc).Ticks;
var ts = ticks / TimeSpan.TicksPerSecond;
return ts;
}
/// <summary>
/// Converts the given date value to epoch time.
/// </summary>
public static long ToEpochTime(this DateTimeOffset dateTime)
{
var date = dateTime.ToUniversalTime();
var ticks = date.Ticks - new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.Zero).Ticks;
var ts = ticks / TimeSpan.TicksPerSecond;
return ts;
}
/// <summary>
/// Converts the given epoch time to a <see cref="DateTime"/> with <see cref="DateTimeKind.Utc"/> kind.
/// </summary>
public static DateTime ToDateTimeFromEpoch(this long intDate)
{
var timeInTicks = intDate * TimeSpan.TicksPerSecond;
return new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc).AddTicks(timeInTicks);
}
/// <summary>
/// Converts the given epoch time to a UTC <see cref="DateTimeOffset"/>.
/// </summary>
public static DateTimeOffset ToDateTimeOffsetFromEpoch(this long intDate)
{
var timeInTicks = intDate * TimeSpan.TicksPerSecond;
return new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.Zero).AddTicks(timeInTicks);
}
}
Unix epoch is now part of DateTime class. Converting millis to DateTime is as easy as
DateTime.UnixEpoch.AddMilliseconds(millis)
To supplement ScottCher's answer, I recently found myself in the annoying scenario of having both seconds and milliseconds UNIX timestamps arbitrarily mixed together in an input data set. The following code seems to handle this well:
static readonly DateTime UnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
static readonly double MaxUnixSeconds = (DateTime.MaxValue - UnixEpoch).TotalSeconds;
public static DateTime UnixTimeStampToDateTime(double unixTimeStamp)
{
return unixTimeStamp > MaxUnixSeconds
? UnixEpoch.AddMilliseconds(unixTimeStamp)
: UnixEpoch.AddSeconds(unixTimeStamp);
}
Unix time conversion is new in .NET Framework 4.6.
You can now more easily convert date and time values to or from .NET Framework types and Unix time. This can be necessary, for example, when converting time values between a JavaScript client and .NET server. The following APIs have been added to the DateTimeOffset structure:
static DateTimeOffset FromUnixTimeSeconds(long seconds)
static DateTimeOffset FromUnixTimeMilliseconds(long milliseconds)
long DateTimeOffset.ToUnixTimeSeconds()
long DateTimeOffset.ToUnixTimeMilliseconds()
In C# 8.0 (.NET Core 2.1) it is a simple one liner:
DateTime.UnixEpoch.AddSeconds(unixTimeInSeconds)
var dt = DateTime.Now;
var unixTime = ((DateTimeOffset)dt).ToUnixTimeSeconds();
// 1510396991
var dt = DateTimeOffset.FromUnixTimeSeconds(1510396991);
// [11.11.2017 10:43:11 +00:00]
I found the right answer just by comparing the conversion to 1/1/1970 w/o the local time adjustment;
DateTime date = new DateTime(2011, 4, 1, 12, 0, 0, 0);
DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, 0);
TimeSpan span = (date - epoch);
double unixTime =span.TotalSeconds;
From .net 4.6, you can do this:
var dateTime = DateTimeOffset.FromUnixTimeSeconds(unixDateTime).DateTime;
Written a simplest extension that works for us. If anyone looks for it...
public static class DateTimeExtensions
{
public static DateTime FromUnixTimeStampToDateTime(this string unixTimeStamp)
{
return DateTimeOffset.FromUnixTimeSeconds(long.Parse(unixTimeStamp)).UtcDateTime;
}
}
System.DateTimeOffset.Now.ToUnixTimeSeconds()
DateTime unixEpoch = DateTime.ParseExact("1970-01-01", "yyyy-MM-dd", System.Globalization.CultureInfo.InvariantCulture);
DateTime convertedTime = unixEpoch.AddMilliseconds(unixTimeInMillisconds);
Of course, one can make unixEpoch a global static, so it only needs to appear once in your project, and one can use AddSeconds if the UNIX time is in seconds.
To go the other way:
double unixTimeInMilliseconds = timeToConvert.Subtract(unixEpoch).TotalMilliseconds;
Truncate to Int64 and/or use TotalSeconds as needed.
A Unix tick is 1 second (if I remember well), and a .NET tick is 100 nanoseconds.
If you've been encountering problems with nanoseconds, you might want to try using AddTick(10000000 * value).
I needed to convert a timeval struct (seconds, microseconds) containing UNIX time to DateTime without losing precision and haven't found an answer here so I thought I just might add mine:
DateTime _epochTime = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
private DateTime UnixTimeToDateTime(Timeval unixTime)
{
return _epochTime.AddTicks(
unixTime.Seconds * TimeSpan.TicksPerSecond +
unixTime.Microseconds * TimeSpan.TicksPerMillisecond/1000);
}
public static class UnixTime
{
private static readonly DateTime Epoch = new DateTime(1970, 1, 1, 0, 0, 0, 0);
public static DateTime UnixTimeToDateTime(double unixTimeStamp)
{
return Epoch.AddSeconds(unixTimeStamp).ToUniversalTime();
}
}
you can call UnixTime.UnixTimeToDateTime(double datetime))
For .NET 4.6 and later:
public static class UnixDateTime
{
public static DateTimeOffset FromUnixTimeSeconds(long seconds)
{
if (seconds < -62135596800L || seconds > 253402300799L)
throw new ArgumentOutOfRangeException("seconds", seconds, "");
return new DateTimeOffset(seconds * 10000000L + 621355968000000000L, TimeSpan.Zero);
}
public static DateTimeOffset FromUnixTimeMilliseconds(long milliseconds)
{
if (milliseconds < -62135596800000L || milliseconds > 253402300799999L)
throw new ArgumentOutOfRangeException("milliseconds", milliseconds, "");
return new DateTimeOffset(milliseconds * 10000L + 621355968000000000L, TimeSpan.Zero);
}
public static long ToUnixTimeSeconds(this DateTimeOffset utcDateTime)
{
return utcDateTime.Ticks / 10000000L - 62135596800L;
}
public static long ToUnixTimeMilliseconds(this DateTimeOffset utcDateTime)
{
return utcDateTime.Ticks / 10000L - 62135596800000L;
}
[Test]
public void UnixSeconds()
{
DateTime utcNow = DateTime.UtcNow;
DateTimeOffset utcNowOffset = new DateTimeOffset(utcNow);
long unixTimestampInSeconds = utcNowOffset.ToUnixTimeSeconds();
DateTimeOffset utcNowOffsetTest = UnixDateTime.FromUnixTimeSeconds(unixTimestampInSeconds);
Assert.AreEqual(utcNowOffset.Year, utcNowOffsetTest.Year);
Assert.AreEqual(utcNowOffset.Month, utcNowOffsetTest.Month);
Assert.AreEqual(utcNowOffset.Date, utcNowOffsetTest.Date);
Assert.AreEqual(utcNowOffset.Hour, utcNowOffsetTest.Hour);
Assert.AreEqual(utcNowOffset.Minute, utcNowOffsetTest.Minute);
Assert.AreEqual(utcNowOffset.Second, utcNowOffsetTest.Second);
}
[Test]
public void UnixMilliseconds()
{
DateTime utcNow = DateTime.UtcNow;
DateTimeOffset utcNowOffset = new DateTimeOffset(utcNow);
long unixTimestampInMilliseconds = utcNowOffset.ToUnixTimeMilliseconds();
DateTimeOffset utcNowOffsetTest = UnixDateTime.FromUnixTimeMilliseconds(unixTimestampInMilliseconds);
Assert.AreEqual(utcNowOffset.Year, utcNowOffsetTest.Year);
Assert.AreEqual(utcNowOffset.Month, utcNowOffsetTest.Month);
Assert.AreEqual(utcNowOffset.Date, utcNowOffsetTest.Date);
Assert.AreEqual(utcNowOffset.Hour, utcNowOffsetTest.Hour);
Assert.AreEqual(utcNowOffset.Minute, utcNowOffsetTest.Minute);
Assert.AreEqual(utcNowOffset.Second, utcNowOffsetTest.Second);
Assert.AreEqual(utcNowOffset.Millisecond, utcNowOffsetTest.Millisecond);
}
}
How come that s returns 7942 when it should be 13 minutes aka roughly 780 seconds?
var s = Math.Round((DateTime.Now - FromUnixTime(1589414482)).TotalSeconds);
DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
var date = DateTime.Now;
DateTime FromUnixTime(long unixTime)
{
return epoch.AddSeconds(unixTime);
}
DateTime.Now returns a local time. Unix Epoch times are based on UTC. That's your difference.
There is this example code, but then it starts talking about millisecond / nanosecond problems.
The same question is on MSDN, Seconds since the Unix epoch in C#.
This is what I've got so far:
public Double CreatedEpoch
{
get
{
DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, 0).ToLocalTime();
TimeSpan span = (this.Created.ToLocalTime() - epoch);
return span.TotalSeconds;
}
set
{
DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, 0).ToLocalTime();
this.Created = epoch.AddSeconds(value);
}
}
Here's what you need:
public static DateTime UnixTimeStampToDateTime( double unixTimeStamp )
{
// Unix timestamp is seconds past epoch
DateTime dateTime = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
dateTime = dateTime.AddSeconds( unixTimeStamp ).ToLocalTime();
return dateTime;
}
Or, for Java (which is different because the timestamp is in milliseconds, not seconds):
public static DateTime JavaTimeStampToDateTime( double javaTimeStamp )
{
// Java timestamp is milliseconds past epoch
DateTime dateTime = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
dateTime = dateTime.AddMilliseconds( javaTimeStamp ).ToLocalTime();
return dateTime;
}
The latest version of .NET (v4.6) has added built-in support for Unix time conversions. That includes both to and from Unix time represented by either seconds or milliseconds.
Unix time in seconds to UTC DateTimeOffset:
DateTimeOffset dateTimeOffset = DateTimeOffset.FromUnixTimeSeconds(1000);
DateTimeOffset to Unix time in seconds:
long unixTimeStampInSeconds = dateTimeOffset.ToUnixTimeSeconds();
Unix time in milliseconds to UTC DateTimeOffset:
DateTimeOffset dateTimeOffset = DateTimeOffset.FromUnixTimeMilliseconds(1000000);
DateTimeOffset to Unix time in milliseconds:
long unixTimeStampInMilliseconds = dateTimeOffset.ToUnixTimeMilliseconds();
Note: These methods convert to and from a UTC DateTimeOffset. To get a DateTime representation simply use the DateTimeOffset.UtcDateTime or DateTimeOffset.LocalDateTime properties:
DateTime dateTime = dateTimeOffset.UtcDateTime;
DateTime to UNIX timestamp:
public static double DateTimeToUnixTimestamp(DateTime dateTime)
{
return (TimeZoneInfo.ConvertTimeToUtc(dateTime) -
new DateTime(1970, 1, 1, 0, 0, 0, 0, System.DateTimeKind.Utc)).TotalSeconds;
}
From Wikipedia:
UTC does not change with a change of seasons, but local time or civil time may change if a time zone jurisdiction observes daylight saving time (summer time). For example, local time on the east coast of the United States is five hours behind UTC during winter, but four hours behind while daylight saving is observed there.
So this is my code:
TimeSpan span = (DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0,DateTimeKind.Utc));
double unixTime = span.TotalSeconds;
You can use DateTimeOffset.
For example. I have a DateTime object
var dateTime1 = DateTime.Now;
If I want to convert it to the Unix time stamps, it can be achieved as follows
var unixTimeSeconds = new DateTimeOffset(dateTime1).ToUnixTimeSeconds()
If you want convert unix timeStamp to normal DateTime, you can use this code piece:
var dateTime2 = DateTimeOffset.FromUnixTimeSeconds(unixTimeSeconds).LocalDateTime;
or
var dateTime2 = DateTimeOffset.FromUnixTimeSeconds(unixTimeSeconds).UtcDateTime;
For more information please visit this link :
DateTimeOffset.ToUnixTimeSeconds Method,
DateTimeOffset.FromUnixTimeSeconds
Be careful, if you need precision higher than milliseconds!
.NET (v4.6) methods (e.g. FromUnixTimeMilliseconds) don't provide this precision.
AddSeconds and AddMilliseconds also cut off the microseconds in the double.
These versions have high precision:
Unix -> DateTime
public static DateTime UnixTimestampToDateTime(double unixTime)
{
DateTime unixStart = new DateTime(1970, 1, 1, 0, 0, 0, 0, System.DateTimeKind.Utc);
long unixTimeStampInTicks = (long) (unixTime * TimeSpan.TicksPerSecond);
return new DateTime(unixStart.Ticks + unixTimeStampInTicks, System.DateTimeKind.Utc);
}
DateTime -> Unix
public static double DateTimeToUnixTimestamp(DateTime dateTime)
{
DateTime unixStart = new DateTime(1970, 1, 1, 0, 0, 0, 0, System.DateTimeKind.Utc);
long unixTimeStampInTicks = (dateTime.ToUniversalTime() - unixStart).Ticks;
return (double) unixTimeStampInTicks / TimeSpan.TicksPerSecond;
}
See IdentityModel.EpochTimeExtensions
public static class EpochTimeExtensions
{
/// <summary>
/// Converts the given date value to epoch time.
/// </summary>
public static long ToEpochTime(this DateTime dateTime)
{
var date = dateTime.ToUniversalTime();
var ticks = date.Ticks - new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc).Ticks;
var ts = ticks / TimeSpan.TicksPerSecond;
return ts;
}
/// <summary>
/// Converts the given date value to epoch time.
/// </summary>
public static long ToEpochTime(this DateTimeOffset dateTime)
{
var date = dateTime.ToUniversalTime();
var ticks = date.Ticks - new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.Zero).Ticks;
var ts = ticks / TimeSpan.TicksPerSecond;
return ts;
}
/// <summary>
/// Converts the given epoch time to a <see cref="DateTime"/> with <see cref="DateTimeKind.Utc"/> kind.
/// </summary>
public static DateTime ToDateTimeFromEpoch(this long intDate)
{
var timeInTicks = intDate * TimeSpan.TicksPerSecond;
return new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc).AddTicks(timeInTicks);
}
/// <summary>
/// Converts the given epoch time to a UTC <see cref="DateTimeOffset"/>.
/// </summary>
public static DateTimeOffset ToDateTimeOffsetFromEpoch(this long intDate)
{
var timeInTicks = intDate * TimeSpan.TicksPerSecond;
return new DateTimeOffset(1970, 1, 1, 0, 0, 0, TimeSpan.Zero).AddTicks(timeInTicks);
}
}
Unix epoch is now part of DateTime class. Converting millis to DateTime is as easy as
DateTime.UnixEpoch.AddMilliseconds(millis)
To supplement ScottCher's answer, I recently found myself in the annoying scenario of having both seconds and milliseconds UNIX timestamps arbitrarily mixed together in an input data set. The following code seems to handle this well:
static readonly DateTime UnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
static readonly double MaxUnixSeconds = (DateTime.MaxValue - UnixEpoch).TotalSeconds;
public static DateTime UnixTimeStampToDateTime(double unixTimeStamp)
{
return unixTimeStamp > MaxUnixSeconds
? UnixEpoch.AddMilliseconds(unixTimeStamp)
: UnixEpoch.AddSeconds(unixTimeStamp);
}
Unix time conversion is new in .NET Framework 4.6.
You can now more easily convert date and time values to or from .NET Framework types and Unix time. This can be necessary, for example, when converting time values between a JavaScript client and .NET server. The following APIs have been added to the DateTimeOffset structure:
static DateTimeOffset FromUnixTimeSeconds(long seconds)
static DateTimeOffset FromUnixTimeMilliseconds(long milliseconds)
long DateTimeOffset.ToUnixTimeSeconds()
long DateTimeOffset.ToUnixTimeMilliseconds()
In C# 8.0 (.NET Core 2.1) it is a simple one liner:
DateTime.UnixEpoch.AddSeconds(unixTimeInSeconds)
var dt = DateTime.Now;
var unixTime = ((DateTimeOffset)dt).ToUnixTimeSeconds();
// 1510396991
var dt = DateTimeOffset.FromUnixTimeSeconds(1510396991);
// [11.11.2017 10:43:11 +00:00]
I found the right answer just by comparing the conversion to 1/1/1970 w/o the local time adjustment;
DateTime date = new DateTime(2011, 4, 1, 12, 0, 0, 0);
DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, 0);
TimeSpan span = (date - epoch);
double unixTime =span.TotalSeconds;
From .net 4.6, you can do this:
var dateTime = DateTimeOffset.FromUnixTimeSeconds(unixDateTime).DateTime;
Written a simplest extension that works for us. If anyone looks for it...
public static class DateTimeExtensions
{
public static DateTime FromUnixTimeStampToDateTime(this string unixTimeStamp)
{
return DateTimeOffset.FromUnixTimeSeconds(long.Parse(unixTimeStamp)).UtcDateTime;
}
}
System.DateTimeOffset.Now.ToUnixTimeSeconds()
DateTime unixEpoch = DateTime.ParseExact("1970-01-01", "yyyy-MM-dd", System.Globalization.CultureInfo.InvariantCulture);
DateTime convertedTime = unixEpoch.AddMilliseconds(unixTimeInMillisconds);
Of course, one can make unixEpoch a global static, so it only needs to appear once in your project, and one can use AddSeconds if the UNIX time is in seconds.
To go the other way:
double unixTimeInMilliseconds = timeToConvert.Subtract(unixEpoch).TotalMilliseconds;
Truncate to Int64 and/or use TotalSeconds as needed.
A Unix tick is 1 second (if I remember well), and a .NET tick is 100 nanoseconds.
If you've been encountering problems with nanoseconds, you might want to try using AddTick(10000000 * value).
I needed to convert a timeval struct (seconds, microseconds) containing UNIX time to DateTime without losing precision and haven't found an answer here so I thought I just might add mine:
DateTime _epochTime = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
private DateTime UnixTimeToDateTime(Timeval unixTime)
{
return _epochTime.AddTicks(
unixTime.Seconds * TimeSpan.TicksPerSecond +
unixTime.Microseconds * TimeSpan.TicksPerMillisecond/1000);
}
public static class UnixTime
{
private static readonly DateTime Epoch = new DateTime(1970, 1, 1, 0, 0, 0, 0);
public static DateTime UnixTimeToDateTime(double unixTimeStamp)
{
return Epoch.AddSeconds(unixTimeStamp).ToUniversalTime();
}
}
you can call UnixTime.UnixTimeToDateTime(double datetime))
For .NET 4.6 and later:
public static class UnixDateTime
{
public static DateTimeOffset FromUnixTimeSeconds(long seconds)
{
if (seconds < -62135596800L || seconds > 253402300799L)
throw new ArgumentOutOfRangeException("seconds", seconds, "");
return new DateTimeOffset(seconds * 10000000L + 621355968000000000L, TimeSpan.Zero);
}
public static DateTimeOffset FromUnixTimeMilliseconds(long milliseconds)
{
if (milliseconds < -62135596800000L || milliseconds > 253402300799999L)
throw new ArgumentOutOfRangeException("milliseconds", milliseconds, "");
return new DateTimeOffset(milliseconds * 10000L + 621355968000000000L, TimeSpan.Zero);
}
public static long ToUnixTimeSeconds(this DateTimeOffset utcDateTime)
{
return utcDateTime.Ticks / 10000000L - 62135596800L;
}
public static long ToUnixTimeMilliseconds(this DateTimeOffset utcDateTime)
{
return utcDateTime.Ticks / 10000L - 62135596800000L;
}
[Test]
public void UnixSeconds()
{
DateTime utcNow = DateTime.UtcNow;
DateTimeOffset utcNowOffset = new DateTimeOffset(utcNow);
long unixTimestampInSeconds = utcNowOffset.ToUnixTimeSeconds();
DateTimeOffset utcNowOffsetTest = UnixDateTime.FromUnixTimeSeconds(unixTimestampInSeconds);
Assert.AreEqual(utcNowOffset.Year, utcNowOffsetTest.Year);
Assert.AreEqual(utcNowOffset.Month, utcNowOffsetTest.Month);
Assert.AreEqual(utcNowOffset.Date, utcNowOffsetTest.Date);
Assert.AreEqual(utcNowOffset.Hour, utcNowOffsetTest.Hour);
Assert.AreEqual(utcNowOffset.Minute, utcNowOffsetTest.Minute);
Assert.AreEqual(utcNowOffset.Second, utcNowOffsetTest.Second);
}
[Test]
public void UnixMilliseconds()
{
DateTime utcNow = DateTime.UtcNow;
DateTimeOffset utcNowOffset = new DateTimeOffset(utcNow);
long unixTimestampInMilliseconds = utcNowOffset.ToUnixTimeMilliseconds();
DateTimeOffset utcNowOffsetTest = UnixDateTime.FromUnixTimeMilliseconds(unixTimestampInMilliseconds);
Assert.AreEqual(utcNowOffset.Year, utcNowOffsetTest.Year);
Assert.AreEqual(utcNowOffset.Month, utcNowOffsetTest.Month);
Assert.AreEqual(utcNowOffset.Date, utcNowOffsetTest.Date);
Assert.AreEqual(utcNowOffset.Hour, utcNowOffsetTest.Hour);
Assert.AreEqual(utcNowOffset.Minute, utcNowOffsetTest.Minute);
Assert.AreEqual(utcNowOffset.Second, utcNowOffsetTest.Second);
Assert.AreEqual(utcNowOffset.Millisecond, utcNowOffsetTest.Millisecond);
}
}
I am working in Firefox's places.sqlite file and need to convert the local DateTime to PRTime, using C#. PRTime is "a 64-bit integer representing the number of microseconds since midnight (00:00:00) 1 January 1970 Coordinated Universal Time (UTC)) to a datetime."
This can be achieved with this little helper class here:
public static class TimeHelper
{
// PRTime is Int64 count of microseconds from 1970-01-01-00-00-0000
static Int64 ToPRTime(DateTime dateTime)
{
TimeSpan t = (dateTime - new DateTime(1970, 1, 1));
return Convert.ToInt64(t.TotalMilliseconds * 1000);
}
static DateTime FromPrTime(Int64 prTime)
{
var someDate = new System.DateTime(1970, 1, 1, 0, 0, 0, 0);
var milliSeconds = prTime / 1000;
return someDate.AddMilliseconds(milliSeconds);
}
}
How do you convert Unix epoch time into real time in C#? (Epoch beginning 1/1/1970)
UPDATE 2020
You can do this with DateTimeOffset
DateTimeOffset dateTimeOffset = DateTimeOffset.FromUnixTimeSeconds(epochSeconds);
DateTimeOffset dateTimeOffset2 = DateTimeOffset.FromUnixTimeMilliseconds(epochMilliseconds);
And if you need the DateTime object instead of DateTimeOffset, then you can call the DateTime property
DateTime dateTime = dateTimeOffset.DateTime;
Original answer
I presume that you mean Unix time, which is defined as the number of seconds since midnight (UTC) on 1st January 1970.
private static readonly DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
public static DateTime FromUnixTime(long unixTime)
{
return epoch.AddSeconds(unixTime);
}
The latest version of .Net (v4.6) just added built-in support for Unix time conversions. That includes both to and from Unix time represented by either seconds or milliseconds.
Unix time in seconds to DateTimeOffset:
DateTimeOffset dateTimeOffset = DateTimeOffset.FromUnixTimeSeconds(1000);
DateTimeOffset to Unix time in seconds:
long unixTimeStampInSeconds = dateTimeOffset.ToUnixTimeSeconds();
Unix time in milliseconds to DateTimeOffset:
DateTimeOffset dateTimeOffset = DateTimeOffset.FromUnixTimeMilliseconds(1000000);
DateTimeOffset to Unix time in milliseconds:
long unixTimeStampInMilliseconds= dateTimeOffset.ToUnixTimeMilliseconds();
Note: These methods convert to and from DateTimeOffset. To get a DateTime representation simply use the DateTimeOffset.DateTime property:
DateTime dateTime = dateTimeOffset.UtcDateTime;
With all credit to LukeH, I've put together some extension methods for easy use:
public static DateTime FromUnixTime(this long unixTime)
{
var epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
return epoch.AddSeconds(unixTime);
}
public static long ToUnixTime(this DateTime date)
{
var epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
return Convert.ToInt64((date - epoch).TotalSeconds);
}
Note the comment below from CodesInChaos that the above FromUnixTime returns a DateTime with a Kind of Utc, which is fine, but the above ToUnixTime is much more suspect in that doesn't account for what kind of DateTime the given date is. To allow for date's Kind being either Utc or Local, use ToUniversalTime:
public static long ToUnixTime(this DateTime date)
{
var epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
return Convert.ToInt64((date.ToUniversalTime() - epoch).TotalSeconds);
}
ToUniversalTime will convert a Local (or Unspecified) DateTime to Utc.
if you dont want to create the epoch DateTime instance when moving from DateTime to epoch you can also do:
public static long ToUnixTime(this DateTime date)
{
return (date.ToUniversalTime().Ticks - 621355968000000000) / 10000000;
}
You actually want to AddMilliseconds(milliseconds), not seconds. Adding seconds will give you an out of range exception.
The Unix epoch is the number of seconds that have elapsed since January 1, 1970 at midnight UTC time minus the leap seconds. This means that at midnight of January 1, 1970, Unix time was 0. The Unix epoch is also called Unix time, POSIX time, or Unix timestamp.
With .Net Framework 4.6 or higher Use the method DateTimeOffset.ToUnixTimeMilliseconds() It returns the number of milliseconds that have elapsed since 1970-01-01T00:00:00.000Z.
var EPOCH = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();
It's well documented here DateTimeOffset.ToUnixTimeMilliseconds
To get the EPOCH with seconds only you may use
var Epoch = (int)(DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)).TotalSeconds;
and convert the Epoch to DateTime with the following method
private DateTime Epoch2UTCNow(int epoch)
{
return new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc).AddSeconds(epoch);
}
But Since
On systems where the representation of Unix time is as a signed 32-bit number, the representation will end after 231 - 1 seconds which will happen at 3:14:08 on 19 January 2038 UTC. This is called the Year 2038 problem where the 32-bit signed Unix time will overflow.
I suggest to save it as long not int as EPOCH_2038_SAFE
long EPOCH_2038_SAFE =
(long)(DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc)).TotalSeconds;
If you are looking for more, use the following with more ticks precision
long EPOCH = DateTime.UtcNow.Ticks - new DateTime(1970, 1, 1,0,0,0,0).Ticks;
If you want better performance you can use this version.
public const long UnixEpochTicks = 621355968000000000;
public const long TicksPerMillisecond = 10000;
public const long TicksPerSecond = TicksPerMillisecond * 1000;
//[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static DateTime FromUnixTimestamp(this long unixTime)
{
return new DateTime(UnixEpochTicks + unixTime * TicksPerSecond);
}
From a quick benchmark (BenchmarkDotNet) under net471 I get this number:
Method | Mean | Error | StdDev | Scaled |
-------------- |---------:|----------:|----------:|-------:|
LukeH | 5.897 ns | 0.0897 ns | 0.0795 ns | 1.00 |
MyCustom | 3.176 ns | 0.0573 ns | 0.0536 ns | 0.54 |
2x faster against LukeH's version (if the performance mater)
This is similar to how DateTime internally work.
// convert datetime to unix epoch seconds
public static long ToUnixTime(DateTime date)
{
var epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
return Convert.ToInt64((date.ToUniversalTime() - epoch).TotalSeconds);
}
Should use ToUniversalTime() for the DateTime object.
currently you can simply use
DateTimeOffset.UtcNow.ToUnixTimeMilliseconds()
it will be returned as a 64-bits long
I use following extension methods for epoch conversion
public static int GetEpochSeconds(this DateTime date)
{
TimeSpan t = DateTime.UtcNow - new DateTime(1970, 1, 1);
return (int)t.TotalSeconds;
}
public static DateTime FromEpochSeconds(this DateTime date, long EpochSeconds)
{
var epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
return epoch.AddSeconds(EpochSeconds);
}
Since .Net 4.6 and above please use
DateTimeOffset.Now.ToUnixTimeSeconds()
To not worry about using milliseconds or seconds just do:
public static DateTime _ToDateTime(this long unixEpochTime)
{
DateTime epoch = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
var date = epoch.AddMilliseconds(unixEpochTime);
if (date.Year > 1972)
return date;
return epoch.AddSeconds(unixEpochTime);
}
If epoch time is in seconds then there is no way you can pass year 1972 adding milliseconds.
If you are not using 4.6, this may help Source: System.IdentityModel.Tokens
/// <summary>
/// DateTime as UTV for UnixEpoch
/// </summary>
public static readonly DateTime UnixEpoch = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
/// <summary>
/// Per JWT spec:
/// Gets the number of seconds from 1970-01-01T0:0:0Z as measured in UTC until the desired date/time.
/// </summary>
/// <param name="datetime">The DateTime to convert to seconds.</param>
/// <remarks>if dateTimeUtc less than UnixEpoch, return 0</remarks>
/// <returns>the number of seconds since Unix Epoch.</returns>
public static long GetIntDate(DateTime datetime)
{
DateTime dateTimeUtc = datetime;
if (datetime.Kind != DateTimeKind.Utc)
{
dateTimeUtc = datetime.ToUniversalTime();
}
if (dateTimeUtc.ToUniversalTime() <= UnixEpoch)
{
return 0;
}
return (long)(dateTimeUtc - UnixEpoch).TotalSeconds;
}
In case you need to convert a timeval struct (seconds, microseconds) containing UNIX time to DateTime without losing precision, this is how:
DateTime _epochTime = new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
private DateTime UnixTimeToDateTime(Timeval unixTime)
{
return _epochTime.AddTicks(
unixTime.Seconds * TimeSpan.TicksPerSecond +
unixTime.Microseconds * TimeSpan.TicksPerMillisecond/1000);
}
Here is my solution:
public long GetTime()
{
DateTime dtCurTime = DateTime.Now.ToUniversalTime();
DateTime dtEpochStartTime = Convert.ToDateTime("1/1/1970 0:00:00 AM");
TimeSpan ts = dtCurTime.Subtract(dtEpochStartTime);
double epochtime;
epochtime = ((((((ts.Days * 24) + ts.Hours) * 60) + ts.Minutes) * 60) + ts.Seconds);
return Convert.ToInt64(epochtime);
}