ISO 8601 Date Converter
Parse, validate, and convert any ISO 8601 date or timestamp. Paste an extended timestamp like 2026-06-19T14:30:00Z, a week date like 2026-W25-5, an ordinal date like 2026-170, or a basic format with a timezone offset, and instantly see whether it is valid plus its human-readable form, UTC ISO 8601, Unix epoch in seconds and milliseconds, day of week, week date, ordinal date, RFC 1123 string, and how long ago or away it is. Everything runs in your browser.
ToolsSoup's ISO 8601 Date Converter is a free online tool that parses, validates, and converts any ISO 8601 date or timestamp. Unlike a date picker, it reads whatever ISO 8601 string you paste — the common extended form like 2026-06-19T14:30:00Z, the compact basic form 20260619T143000+0200, week dates such as 2026-W25-5, and ordinal (day-of-year) dates like 2026-170 — then tells you if it is valid and breaks it down into a human-readable date, the canonical UTC ISO 8601 timestamp, the Unix epoch in seconds and milliseconds, the day of the week, the ISO week date, the ordinal date, an RFC 1123 string, and how far it is from right now. Everything runs locally in your browser, so your data is never uploaded.
What is ISO 8601?
ISO 8601 is the international standard for writing dates and times so that they are unambiguous across countries and systems. Instead of formats like 06/19/2026 that mean different things in different regions, ISO 8601 writes the date from largest unit to smallest — year, month, day — as 2026-06-19, and adds a time after a 'T' separator, like 2026-06-19T14:30:00. A trailing 'Z' means the time is in UTC, while a suffix like +02:00 records the offset from UTC. Because the format sorts correctly as plain text and removes regional ambiguity, it is the default for APIs, databases, logs, and configuration files.
Which ISO 8601 formats does this converter accept?
This tool understands the full range of ISO 8601 date representations, not just the everyday timestamp:
- Calendar dates in extended (2026-06-19) and basic (20260619) form, with optional time and a Z, +hh:mm, or +hhmm timezone designator.
- Week dates such as 2026-W25 or 2026-W25-5, where the final digit is the ISO weekday (1 = Monday, 7 = Sunday).
- Ordinal dates such as 2026-170, which means the 170th day of the year.
- Fractional seconds (2026-06-19T14:30:00.250Z) and the special 24:00 end-of-day time.
How to convert an ISO 8601 date
Conversion happens instantly as you type — there is no button to press:
- Paste or type an ISO 8601 date or timestamp into the input, or click one of the example chips to load a sample.
- Check the status badge to confirm the string is valid ISO 8601.
- Read the converted values — human-readable UTC, the canonical ISO 8601 timestamp, the Unix epoch, the ISO week date, the ordinal date, and more.
- Click Copy to grab the full breakdown, or Use now to inspect the current moment as ISO 8601.
How is this different from the UTC converter?
The UTC converter takes a date and a time from picker fields and moves them between your local zone and UTC. This ISO 8601 converter goes the other way: you hand it a finished ISO 8601 string — including formats a picker can't produce, like week dates and ordinal dates — and it validates and decodes it. Use the UTC converter to build a UTC time from scratch, and use this tool to understand, check, or reformat an ISO 8601 string you already have.
Why use this ISO 8601 converter?
- Parses extended and basic calendar dates, week dates, and ordinal dates.
- Validates the string and clearly flags anything that is not legal ISO 8601.
- Shows the Unix epoch in both seconds and milliseconds for developers.
- Honors any timezone offset or Z in the input and normalizes to UTC.
- Reveals the ISO week date and ordinal (day-of-year) date for any timestamp.
- Tells you how long ago or how far in the future the moment is.
- Runs entirely in your browser — nothing you paste is uploaded or stored.
Frequently asked questions
What does the Z at the end of an ISO 8601 timestamp mean?
The Z is the 'Zulu' designator and means the time is in UTC, i.e. an offset of +00:00. A timestamp like 2026-06-19T14:30:00Z is 14:30 UTC. If a timestamp has no Z and no offset, this tool reads it as UTC and labels the offset as 'None (read as UTC).'
What is an ISO week date like 2026-W25-5?
It identifies a day by its ISO week number and weekday instead of month and day. 2026-W25-5 is the Friday (weekday 5) of the 25th ISO week of 2026. ISO weeks start on Monday, and week 1 is the week containing the year's first Thursday, so the ISO week-numbering year can differ from the calendar year near January 1.
What is an ordinal date like 2026-170?
An ordinal date counts days from the start of the year, so 2026-170 is the 170th day of 2026. It is handy in scientific and logistics contexts. This converter accepts ordinal dates and also reports the ordinal date for any timestamp you enter.
Does it support basic format without dashes and colons?
Yes. ISO 8601 allows a compact 'basic' form that drops the separators, such as 20260619T143000+0200. This tool parses both the basic and the extended (dashed and colon-separated) forms and converts between them by always showing the canonical extended UTC timestamp.
Why is my converted time different from what I entered?
If your input includes a timezone offset like +02:00, the tool converts that instant to UTC, which can change the clock time and even the date. The 'Timezone offset' field shows the offset it detected, and the 'ISO 8601 (UTC)' field shows the equivalent UTC moment.
Is my data kept private?
Yes. All parsing and conversion happens locally in your browser with JavaScript. The dates and timestamps you paste are never sent to or stored on any server.