Your files stay on your device

ISO 8601 duration parser and formatter

Read and write ISO 8601 durations like P1DT2H.
ISO 8601-1 durations · weeks/days/time are exact elapsed time · years and months are nominalClearParse a durationBuild oneISO 8601 duration

P1W · PT30M · -PT90.5S: fractions only on the lowest component, weeks stand alone.
Insert sample

- ISO 8601-1 grammar: weeks are exclusive (P1W, never P1Y2W), fractions only on the lowest-order component, comma or dot as the separator.
- Days and weeks are fixed elapsed time (1 d = 24 h, 1 w = 7 d). Those totals are exact.
- Years and months stay components: no exact millisecond total exists for them, and none is fabricated here.
- Sub-millisecond fractions are truncated, never rounded into the next second.
Paste, drop, or type to begin. Everything stays on this device.

More time & date tools

- Duration converter (/time/duration-converter)
- Date calculator (/time/date-math)
All time & date tools (/time)

Canonical HTML: https://nutter.tools/time/iso-duration/
Markdown version: https://nutter.tools/time/iso-duration/index.md
Plain-text version: https://nutter.tools/time/iso-duration/index.txt
Agent index: https://nutter.tools/llms.txt