ISO 8601 Duration Parser — Convert P3Y6M4DT12H30M5S to Human Time

What is ISO 8601 Duration?

ISO 8601 defines a compact machine-readable format for durations: `PnYnMnDTnHnMnS`, with each letter marking one unit and the `T` separating date from time components. `PT1H30M` is 1 hour 30 minutes. `P2W` is two weeks. This is the format YouTube's Data API returns for video length, Java's Duration.parse() accepts, Kubernetes uses in some manifests, and PostgreSQL and Java both understand as intervals. Working with it manually — especially at API boundaries — is tedious. This tool parses ISO 8601 durations into their components, humanizes them, and also runs the reverse conversion (from a raw total in seconds).

How to work with ISO 8601 durations

1. 1Choose direction: 'Parse ISO → Human' or 'Seconds → ISO'.
2. 2In parse mode, paste an ISO 8601 duration string and read the components, human-readable form, and approximate totals in seconds / minutes / hours.
3. 3In seconds mode, enter a total in seconds and copy the canonicalized ISO 8601 duration.
4. 4Click any sample chip (`P1Y`, `PT1H30M`, `P2W`, …) to see how the format handles different unit combinations.

Tips & Best Practices

• ▸Years and months in ISO 8601 are ambiguous durations — 'P1M' can mean 28, 29, 30, or 31 days depending on the anchor date. For precise math, apply the duration to a specific start date instead of converting to seconds.
• ▸PnW cannot be combined with other components per the strict standard. Most permissive parsers (including this tool) still accept `P2W3D`, but the result may not round-trip through every system.
• ▸The T is required whenever a time component (H/M/S) is present. `P1H` is invalid; `PT1H` is correct.
• ▸Java's Duration.parse() only accepts the day/hour/minute/second subset — no years, months, or weeks. If interop matters, avoid the Y and M fields when producing durations for Java consumers.