--- title: "AbsoluteTime" language: "en" type: "Symbol" summary: "AbsoluteTime[] gives the total number of seconds since the beginning of January 1, 1900, in your time zone. AbsoluteTime[date] gives the absolute time specification corresponding to the given date specification." keywords: - computer time - now - real-time clock - system time - timestamp - datevalue - dateserial - time - timeserial - timevalue - date - dateserial - datevalue - now - time - timeserial - timevalue - today - SYSTIME - clock - clock_t - ctime - localtime - localtime_r - mktime - time - time_t - currentTimeMillis - getTimeInMillis - current-seconds - encode-universal-time - get-decoded-time - get-universal-time - datenum - getabstime - now - timer canonical_url: "https://reference.wolfram.com/language/ref/AbsoluteTime.html" source: "Wolfram Language Documentation" related_guides: - title: "Date & Time" link: "https://reference.wolfram.com/language/guide/DateAndTime.en.md" - title: "External Operations" link: "https://reference.wolfram.com/language/guide/ExternalOperations.en.md" - title: "Time Measurement & Optimization" link: "https://reference.wolfram.com/language/guide/TimeMeasurementAndOptimization.en.md" - title: "Locale & Internationalization" link: "https://reference.wolfram.com/language/guide/LocaleAndInternationalization.en.md" - title: "Cloud Execution Metadata" link: "https://reference.wolfram.com/language/guide/CloudExecutionMetadata.en.md" - title: "Wolfram System Session Information" link: "https://reference.wolfram.com/language/guide/WolframSystemSessionInformation.en.md" related_functions: - title: "UnixTime" link: "https://reference.wolfram.com/language/ref/UnixTime.en.md" - title: "DateList" link: "https://reference.wolfram.com/language/ref/DateList.en.md" - title: "DateString" link: "https://reference.wolfram.com/language/ref/DateString.en.md" - title: "DateObject" link: "https://reference.wolfram.com/language/ref/DateObject.en.md" - title: "JulianDate" link: "https://reference.wolfram.com/language/ref/JulianDate.en.md" - title: "FromAbsoluteTime" link: "https://reference.wolfram.com/language/ref/FromAbsoluteTime.en.md" - title: "DateValue" link: "https://reference.wolfram.com/language/ref/DateValue.en.md" - title: "Now" link: "https://reference.wolfram.com/language/ref/Now.en.md" - title: "SessionTime" link: "https://reference.wolfram.com/language/ref/SessionTime.en.md" - title: "TimeUsed" link: "https://reference.wolfram.com/language/ref/TimeUsed.en.md" - title: "Clock" link: "https://reference.wolfram.com/language/ref/Clock.en.md" - title: "AbsoluteTiming" link: "https://reference.wolfram.com/language/ref/AbsoluteTiming.en.md" - title: "Timing" link: "https://reference.wolfram.com/language/ref/Timing.en.md" - title: "TimeZone" link: "https://reference.wolfram.com/language/ref/TimeZone.en.md" - title: "$TimeUnit" link: "https://reference.wolfram.com/language/ref/$TimeUnit.en.md" - title: "DatePlus" link: "https://reference.wolfram.com/language/ref/DatePlus.en.md" - title: "DateDifference" link: "https://reference.wolfram.com/language/ref/DateDifference.en.md" related_tutorials: - title: "Date and Time Functions" link: "https://reference.wolfram.com/language/tutorial/GlobalAspectsOfWolframSystemSessions.en.md#28650" - title: "Global System Information" link: "https://reference.wolfram.com/language/tutorial/GlobalAspectsOfWolframSystemSessions.en.md#25706" --- # AbsoluteTime AbsoluteTime[] gives the total number of seconds since the beginning of January 1, 1900, in your time zone. AbsoluteTime[date] gives the absolute time specification corresponding to the given date specification. ## Details and Options * ``AbsoluteTime[]`` uses whatever date and time have been set on your computer system. It performs no corrections for time zones, daylight saving time, etc. * In ``AbsoluteTime[date]``, the following date and time specifications can be given as ``date`` : | | | | ------------------ | --------------------------------------------- | | date | DateObject specification | | {y, m, d, h, m, s} | DateList specification | | time | AbsoluteTime specification | | "string" | DateString specification | | {"string", fmt} | date string formed from the specified format | * ``AbsoluteTime[TimeZone -> z]`` gives the date and time inferred for time zone ``z`` by assuming that your computer is set for the time zone specified by ``\$TimeZone``. » * ``AbsoluteTime[]`` is always accurate down to a granularity of ``\$TimeUnit`` seconds, but on many systems is much more accurate. * Shorter lists can be used in ``AbsoluteTime[{y, m, …}]``: ``{y}`` is equivalent to ``{y, 1, 1, 0, 0, 0}``, ``{y, m}`` to ``{y, m, 1, 0, 0, 0}``, etc. * Values of ``m``, ``d``, ``h``, ``m``, ``s`` outside their normal ranges are appropriately reduced. Noninteger values of ``d``, ``h``, ``m``, ``s`` can also be used. » * The number of seconds returned by ``AbsoluteTime`` does not take into account leap seconds. --- ## Examples (18) ### Basic Examples (5) Absolute time in seconds since January 1, 1900: ```wl In[1]:= AbsoluteTime[] Out[1]= 3.852868887409216`16.338359219443774*^9 ``` --- Convert from a date object to an absolute time: ```wl In[1]:= AbsoluteTime[DateObject[{2022, 12, 18}, "Day"]] Out[1]= 3880310400 ``` --- Convert a date list or elided date list: ```wl In[1]:= AbsoluteTime[{2022, 1, 1, 0, 0, 0}] Out[1]= 3849984000 In[2]:= AbsoluteTime[{2022, 1}] Out[2]= 3849984000 ``` --- Convert from a date string to absolute time: ```wl In[1]:= DateString[] Out[1]= "Thu 3 Feb 2022 09:21:50" In[2]:= AbsoluteTime[%] Out[2]= 3852868910 ``` --- Specify date elements for interpreting a string: ```wl In[1]:= AbsoluteTime[{"05/06/22", {"Day", "Month", "YearShort"}}] Out[1]= 3863376000 ``` ### Scope (5) Strings are automatically interpreted when possible: ```wl In[1]:= AbsoluteTime["2022-12-1"] Out[1]= 3878841600 In[2]:= AbsoluteTime["10 March 2022"] Out[2]= 3855859200 ``` --- Separators are assumed if not specified: ```wl In[1]:= AbsoluteTime[{"2/23/2022", {"Month", "Day", "Year"}}] Out[1]= 3854563200 ``` Give explicit separators: ```wl In[2]:= AbsoluteTime[{"2/23/2022", {"Month", "/", "Day", "/", "Year"}}] Out[2]= 3854563200 ``` --- Date lists are converted to standard normalized form: ```wl In[1]:= AbsoluteTime[{2022, 2, 31}] Out[1]= 3855254400 In[2]:= AbsoluteTime[{2022, 3, 3}] Out[2]= 3855254400 ``` --- Day, hour, minute, and second values in input date lists can be noninteger: ```wl In[1]:= AbsoluteTime[{2022, 3, 15.5}] Out[1]= 3.8563344*^9 In[2]:= AbsoluteTime[{2022, 3, 15, 12.3}] Out[2]= 3.85633548*^9 ``` --- The current year is used if not specified in a string: ```wl In[1]:= AbsoluteTime[{"2/15", {"Month", "Day"}}] Out[1]= 3853872000 ``` ### Generalizations & Extensions (1) Give explicit date elements to interpret ambiguous strings: ```wl In[1]:= AbsoluteTime["05/10/1"] ``` AbsoluteTime::ambig: Warning: the interpretation of the string 05/10/1 as a date is ambiguous. ```wl Out[1]= 3198441600 In[2]:= AbsoluteTime[{"05/10/1", {"YearShort", "Day", "Month"}}] Out[2]= 3314304000 ``` ### Options (1) #### TimeZone (1) Find the current absolute time in Greenwich, United Kingdom: ```wl In[1]:= AbsoluteTime[TimeZone -> 0] Out[1]= 3.852890552225737`16.33836166148997*^9 ``` Find the absolute time for a given date using a time zone string: ```wl In[2]:= AbsoluteTime[{2022, 8, 4, 9, 14, 2}, TimeZone -> "America/New_York"] Out[2]= 3868600442 ``` ### Applications (1) Use ``DateListPlot`` to plot data with absolute time $x$ coordinates on a time scale: ```wl In[1]:= DateListPlot[{{3376598400, 2}, {3379276800, 4}, {3381696000, 6}, {3384374400, 8}}] Out[1]= [image] ``` ### Properties & Relations (5) Compute the number of seconds between January 1, 1900, and January 1, 2000: ```wl In[1]:= AbsoluteTime[{2000, 1, 1, 0, 0, 0}] Out[1]= 3155673600 ``` --- ``AbsoluteTime`` represents dates as seconds since the beginning of 1900: ```wl In[1]:= AbsoluteTime[DateObject[{2022, 1, 1}, "Day"]] Out[1]= 3849984000 ``` ``DateObject`` represents a given date: ```wl In[2]:= DateObject[%] Out[2]= DateObject[{2022, 1, 1, 0, 0, 0}, "Instant", "Gregorian", -5.] ``` ``DateList`` represents dates as lists of date elements: ```wl In[3]:= DateList[%] Out[3]= {2022, 1, 1, 0, 0, 0.} ``` ``DateString`` represents dates as strings: ```wl In[4]:= DateString[%] Out[4]= "Sat 1 Jan 2022 00:00:00" ``` --- The number of seconds returned by ``AbsoluteTime`` corresponds to the ``"AbsoluteTime"`` calendar: ```wl In[1]:= now = Now Out[1]= DateObject[{2024, 10, 29, 13, 15, 29.979437}, "Instant", "Gregorian", -5.] In[2]:= AbsoluteTime[now]//DecimalForm Out[2]//DecimalForm= 3.939196529979437`16.347982629933444*^9 In[3]:= CalendarConvert[now, "AbsoluteTime"] Out[3]= DateObject[{3.9391965299794370000000000005`16.347982629933416*^9}, "Instant", "AbsoluteTime", -5.] ``` --- ``UnixTime`` returns the number of seconds since the beginning of 1970, in the GMT time zone: ```wl In[1]:= UnixTime[] Out[1]= 1643901798 ``` Therefore this difference is constant: ```wl In[2]:= IntegerPart[AbsoluteTime[TimeZone -> 0] - UnixTime[]] Out[2]= 2208988800 ``` It is the number of seconds since January 1, 1900, to January 1, 1970: ```wl In[3]:= AbsoluteTime[{1970, 1, 1, 0, 0, 0}] Out[3]= 2208988800 ``` --- ``JulianDate`` returns the number of days since noon on November 24, 4714 BCE in the GMT time zone: ```wl In[1]:= JulianDate[] Out[1]= 2.4596141412339001041666666666603648017725487`18.07995570693812*^6 ``` Therefore this difference is constant: ```wl In[2]:= Round[86400JulianDate[] - AbsoluteTime[TimeZone -> 0]] Out[2]= 208657771200 ``` It is the number of seconds since noon on November 24, 4714 BCE, to the beginning of January 1, 1900: ```wl In[3]:= AbsoluteTime[{-4714, 11, 24, 12, 0, 0}] Out[3]= -208657771200 ``` That proleptic Gregorian date is noon on January 1, 4713 BCE in the Julian calendar: ```wl In[4]:= AbsoluteTime[DateObject[{-4713, 1, 1, 12, 0, 0}, CalendarType -> "Julian"]] Out[4]= -208657771200 ``` ## See Also * [`UnixTime`](https://reference.wolfram.com/language/ref/UnixTime.en.md) * [`DateList`](https://reference.wolfram.com/language/ref/DateList.en.md) * [`DateString`](https://reference.wolfram.com/language/ref/DateString.en.md) * [`DateObject`](https://reference.wolfram.com/language/ref/DateObject.en.md) * [`JulianDate`](https://reference.wolfram.com/language/ref/JulianDate.en.md) * [`FromAbsoluteTime`](https://reference.wolfram.com/language/ref/FromAbsoluteTime.en.md) * [`DateValue`](https://reference.wolfram.com/language/ref/DateValue.en.md) * [`Now`](https://reference.wolfram.com/language/ref/Now.en.md) * [`SessionTime`](https://reference.wolfram.com/language/ref/SessionTime.en.md) * [`TimeUsed`](https://reference.wolfram.com/language/ref/TimeUsed.en.md) * [`Clock`](https://reference.wolfram.com/language/ref/Clock.en.md) * [`AbsoluteTiming`](https://reference.wolfram.com/language/ref/AbsoluteTiming.en.md) * [`Timing`](https://reference.wolfram.com/language/ref/Timing.en.md) * [`TimeZone`](https://reference.wolfram.com/language/ref/TimeZone.en.md) * [`\$TimeUnit`](https://reference.wolfram.com/language/ref/$TimeUnit.en.md) * [`DatePlus`](https://reference.wolfram.com/language/ref/DatePlus.en.md) * [`DateDifference`](https://reference.wolfram.com/language/ref/DateDifference.en.md) ## Tech Notes * [Date and Time Functions](https://reference.wolfram.com/language/tutorial/GlobalAspectsOfWolframSystemSessions.en.md#28650) * [Global System Information](https://reference.wolfram.com/language/tutorial/GlobalAspectsOfWolframSystemSessions.en.md#25706) ## Related Guides * [Date & Time](https://reference.wolfram.com/language/guide/DateAndTime.en.md) * [External Operations](https://reference.wolfram.com/language/guide/ExternalOperations.en.md) * [Time Measurement & Optimization](https://reference.wolfram.com/language/guide/TimeMeasurementAndOptimization.en.md) * [Locale & Internationalization](https://reference.wolfram.com/language/guide/LocaleAndInternationalization.en.md) * [Cloud Execution Metadata](https://reference.wolfram.com/language/guide/CloudExecutionMetadata.en.md) * [Wolfram System Session Information](https://reference.wolfram.com/language/guide/WolframSystemSessionInformation.en.md) ## History * Introduced in 1991 (2.0) \| Updated in 2003 (5.0) ▪ [2007 (6.0)](https://reference.wolfram.com/language/guide/SummaryOfNewFeaturesIn60.en.md) ▪ [2014 (10.0)](https://reference.wolfram.com/language/guide/SummaryOfNewFeaturesIn100.en.md)