ISO 8601 Date Converter
Paste a date in almost any notation and get every ISO 8601 form of it: UTC, with a time zone offset, date only, week date, ordinal date and basic format.
Processed locally in your browser· Your data stays in your browser.
What is ISO 8601 Date Converter?
ISO 8601 is the international standard for writing dates and times, and it comes in several forms: the extended timestamp 2026-09-24T21:00:00Z, the same instant with an offset such as +02:00, the calendar date 2026-09-24, the week date 2026-W39-4, the ordinal date 2026-267 and the compact basic format 20260924T210000Z. APIs, databases, calendars and logs each prefer a different one.
This converter reads dates written as ISO 8601, RFC 2822 (Thu, 24 Sep 2026 21:00:00 +0200), plain text with English, French or Spanish month names (Sep 24 2026 21:00, 24 septembre 2026), Unix timestamps in seconds to nanoseconds, basic-format strings, and ISO week and ordinal dates. A date with no offset is read in the zone you choose, and every result is shown together with ready-to-paste JavaScript, Python and SQL snippets for reading it back.
How does it work?
- Type or paste one date per line in any of the supported notations.
- Pick the zone used to read dates without an offset, and the zone used for the "with offset" form (your browser zone by default).
- Read all the ISO forms in the result table, or choose which one appears in the text output for multi-line input.
- Copy the form you need; use the code snippets to parse it back in your own program.
Common use cases
- Normalising dates from a CSV or spreadsheet into ISO 8601 before importing them into a database.
- Finding the ISO week number and weekday of a delivery date for planning.
- Converting an RFC 2822 email or HTTP header date into the ISO form an API expects.
- Producing filename-friendly basic-format timestamps such as 20260924T210000Z.
Examples
Try this input in the tool above:
Sep 24 2026 21:00
2026-09-24T21:00:00Z
Privacy
ISO 8601 Date Converter runs entirely in your browser. The text or files you provide are processed on your device and are not uploaded, logged or stored on our servers.
Limitations
Numeric dates like 03/04/2026 are ambiguous, so the day/month order is guessed unless you set it; the week and ordinal forms use the calendar date in the zone chosen for the offset form.
Frequently asked questions
What is the difference between "Z" and an offset such as +02:00?
Both name the same instant. Z means UTC, while +02:00 says the local clock is two hours ahead of UTC. 2026-09-24T21:00:00Z and 2026-09-24T23:00:00+02:00 are the same moment.
How do I read 2026-W39-4?
It is ISO week 39 of 2026, day 4 where Monday is 1, so Thursday. ISO week 1 is the week containing the year’s first Thursday, which is why 1 January can belong to the previous year’s week 52 or 53.
What does the tool assume when there is no time zone in my input?
It reads the date as local time in the "zone of the input" option, UTC by default, and says so in a note. A date without a time is taken as midnight in that zone.
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