Duration Calculator
Calculate the exact time between two dates and times — years, months, days, hours, minutes and seconds. Free and instant, no sign-up.
Duration Between Dates
Find the precise difference between two points in time.
About the Duration Calculator
The Duration Calculator finds the exact time between any two moments. Enter a start and end date/time, and OmniWhen returns the difference broken down into years, months, days, hours, minutes and seconds, plus running totals (total days, total hours, total minutes, total seconds).
Useful for project timelines, anniversary calculations, contract durations, or answering "how long ago" / "how long until."
How it works
OmniWhen takes the millisecond difference between your start and end timestamps and breaks it down hierarchically: years come from total months ÷ 12, months from total days ÷ 30, and the remaining days, hours, minutes and seconds are taken from the fractional remainders. Running totals (total days, total hours, total minutes, total seconds) are reported alongside the calendar breakdown so you can pick whichever framing fits your use case.
Examples
- Jan 1, 2024 00:00 → Dec 25, 2024 00:0011 months, 24 days · 359 total days · 8,616 total hours
- Aug 15, 2023 12:00 → Mar 10, 2024 18:306 months, 23 days, 6 hours, 30 minutes · 208 total days
- Dec 31, 2025 23:59:50 → Jan 1, 2026 00:00:0010 seconds