Duration Calculator
Work out exactly how long lies between two moments, in years and months, in days, in weekdays only, or right down to seconds. The calendar is respected properly, so a month from 31 January ends on 28 February rather than spilling into March.
Pick two momentsBoth dates need a value before we can measure between them.
Common questions
- How are months counted?
- By the calendar, not by an average length. One month from 31 January is 28 February, and February's real length is used including in leap years. Dividing by an average month is where most calculators go wrong.
- What does the weekday count include?
- Monday to Friday only, counted as whole days from the start date. It does not account for public holidays, which vary by country.
- Can the end date be earlier than the start?
- Yes. The duration is measured either way and labelled as time until rather than time between, so you can use it for countdowns as well as elapsed time.
- Are my dates remembered?
- Yes, on this device only. Come back and your last two dates are still there. Nothing is sent anywhere.
- Does it handle daylight saving?
- The calendar breakdown uses your local time, so a day remains a day across a clock change. The total-hours figure reflects the real elapsed time, which is where an hour appears or disappears.
- Why does a single day sometimes total 23 or 25 hours?
- Because that is how much time actually passed. On the day a clock goes forward the calendar day is 23 hours long, and on the day it goes back it is 25. The day and week counts are calendar counts, so they still read one day; only the hour, minute and second totals move. Showing 24 there would be inventing an hour that nobody lived through.
Exact. Years, months and days are counted on the calendar in your own time zone, so a day stays a day across a clock change and one month from 31 January is 28 February. The hour, minute and second totals are true elapsed time, which is why a daylight-saving day reads 23 or 25 hours, and the page says so rather than hiding it.