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What is ISO DateTime
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Current ISO DateTime:



Calendar Date Format

Today's calendar date is :

Calendar date representations are in the form shown in the following table.
Extended Format Normal Format
YYYY-MM-DD 2023-12-14 YYYYMMDD 20231214
YYYY-MM 2023-12 - -
[YYYY] indicates a four-digit year, 0000 through 9999.
[MM] indicates a two-digit month of the year, 01 through 12.
[DD] indicates a two-digit day of that month, 01 through 31.

Time Format

Current time is:

ISO 8601 uses the 24-hour clock system. Time representation are in the form shown in the following table.
Extended Format Normal Format
Thh:mm:ss.sss T16:31:45.012 Thhmmss.sss T163145.012
Thh:mm:ss T16:31:45 Thhmmss T163145
Thh:mm T16:31 Thhmm T1631
Thh T16 - -
[hh] refers to a zero-padded hour between 00 and 24.
[mm] refers to a zero-padded minute between 00 and 59.
[ss] refers to a zero-padded second between 00 and 60 (where 60 is only used to denote an added leap second).


If no UTC (Coordinated Universal Time) related information is given with a time representation, the time is assume to be in local time. But it is ambiguous in communication across different timezone.

If the time is in UTC or Greenwich Mean Time (GMT), add "Z" directly after the time with no space. Z is the zone designator for the zero UTC offset.

The UTC offset is the difference in hours and minutes between Coordinated Universal Time (UTC) and local solar time, at a particular place. The UTC offset is appended to the time in the same way that 'Z' was above. Negative UTC offset describe a time zone west of UTC+00:00 where the local time is behind (or early) than UTC. Positive UTC offset describe a time zone east of UTC+00:00 WHERE the local time is ahead (or later) than UTC.
Valid Format
±hh:mm +05:00 ±hhmm +0500 ±hh +05 Z Z

Other ISO Defined Format

Week Date Format

Today's week date is :

Week date representations are in the formats as shown in the following table:
Extended Format Normal Format
YYYY-Www 2023-W03 YYYYWww 2023W03
YYYY-Www-D 2023-W03-4 YYYYWwwD 2023W034
[YYYY] indicates the ISO week-numbering year which is slightly different from the traditional calendar year.
[Www] is the week number prefixed by the letter W, from W01 through W53.
[D] is the weekday number, from 1 through 7, beginning with Monday and ending with Sunday.

There are several mutually equivalent and compatible descriptions of week 01, such as the week with the starting year's first Thursday in it (the formal ISO definition), or the week with 4 January in it. So 1st January may not in week 01 of the year. It only happens when 1st January is on Monday, Tuesday, Wednesday or Thursday. If 1st January is on a Friday, Saturday or Sunday, it is in the last (52 or 53) week of the previous year.

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Week Date:

Ordinal Date Format:

Today's ordinal date is:

Ordinal date representations are in the formats as shown in the following table:
Extended Format Normal Format
YYYY-DDD 2023-237 YYYYDDD 2023203
[YYYY] indicates a year and [DDD] is the "day of year", from 001 through 365 (366 in leap years)

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Ordinal Date:

What is ISO DateTime

ISO 8601 is an international standard covering the worldwide exchange and communication of date and time-related data. It is maintained by the Geneva-based International Organization for Standardization (ISO) and was first published in 1988, with updates in 1991, 2000, 2004, and 2019, and an amendment in 2022. The standard provides a well-defined, unambiguous method of representing calendar dates and times in worldwide communications, especially to avoid misinterpreting numeric dates and times when such data is transferred between countries with different conventions for writing numeric dates and times.