How to use this developer tool
- Enter an ISO 8601 date, duration, or interval.
- Select automatic detection or a specific type.
- Choose strict validation and component output.
- Review normalized and Unix results.
#080 · Time & Date Tools Developer Tool
ISO8601 Converter
Parse, validate, normalize, and generate ISO 8601 calendar dates, timestamps, week dates, ordinal dates, durations, and intervals.
Developer Input
Time & Date ToolsAd space
What this developer tool does
The tool identifies common ISO 8601 representations and converts valid calendar timestamps to normalized UTC and Unix values.
Detect representation → validate calendar or duration syntax → parse components → normalize supported timestamps → report structure.
ISO 8601 durations containing months or years cannot always be reduced to an exact second count without a reference date.
Example
The input 2026-07-11T18:30:45.123+09:00 normalizes to a UTC ISO timestamp while preserving milliseconds.
Tips for better output
- Include an explicit offset for unambiguous timestamps.
- Use Z for UTC.
- Do not treat calendar months in durations as a fixed number of seconds.
FAQ
How do I convert an ISO 8601 timestamp to Unix time?
Parse the timestamp with its offset and divide the resulting milliseconds by 1000.
How do I validate an ISO 8601 date with a timezone offset?
Check the calendar date, time fields, and offset syntax before normalization.
What does Z mean at the end of an ISO 8601 timestamp?
Z indicates that the timestamp is expressed in UTC.
How do I parse an ISO 8601 duration such as P3DT4H?
Read the P-prefixed date and time components into separate duration fields.
What is an ISO 8601 interval?
An interval represents start/end, start/duration, or duration/end notation separated by a slash.
Related developer tools
Supported forms
| Form | Example |
|---|---|
| Calendar timestamp | 2026-07-11T18:30:00+09:00 |
| Week / ordinal date | 2026-W28-6 / 2026-192 |
| Duration / interval | P3DT4H / start/end |