Date & Time
Duration Formatter
Convert seconds ↔ '1h 23m' ↔ '01:23:00' ↔ ISO 8601 'PT1H23M'.
Duration
Accepts: plain seconds (4980), human form (1h 23m), clock (01:23:00) or ISO 8601 (PT1H23M).
Human
1h 23m
Clock (hh:mm:ss)
01:23:00
ISO 8601
PT1H23M
Seconds
4,980
Milliseconds
4,980,000
Days (decimal)
0.0576
About this tool
Type a duration in any common format and see every other format side-by-side. Accepts: a raw number of seconds (4980), human-readable ('1h 23m'), clock-style ('01:23:00'), ISO 8601 ('PT1H23M'), or fractional units ('1.5 days'). Output covers all five forms plus milliseconds and a 'shortest' rendering.
FAQs
What's ISO 8601 duration format?
Starts with 'P', uses Y / M / W / D for date parts and T then H / M / S for time parts. So PT1H23M means 1 hour 23 minutes. P1Y2M3DT4H5M6S is 1 year, 2 months, 3 days, 4 hours, 5 minutes, 6 seconds.
Is the input auto-detected?
Yes - the tool sniffs your input shape and parses accordingly. You can also force a specific source format from a dropdown if auto-detection guesses wrong.
Why does '1 month' look weird in seconds?
Calendar months don't have a fixed length - we approximate using 30.4375 days (average over a 4-year cycle). For exact calendar-aware diffs, use the date-difference tool.
Can it handle negative durations?
Yes - prefix with a minus sign or use ISO 8601's '-' prefix (-PT1H means minus 1 hour).