calc / date & time / DUR

Time Duration Calculator

Two timestamps in, the exact gap out — in calendar form (years, months, days, hours, minutes) and in raw totals for billing, SLAs and log-diving.

Between two moments to the minute

Duration

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Total hours

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§1Two answers, both right

Elapsed time has a calendar form and a metric form, and they answer different questions:

calendar form: years, months, days, hours, minutes (borrow-subtraction — months have unequal lengths) metric form: one number in a single unit total minutes = (B − A) ÷ 60,000 ms

Worked example — project kickoff to launch

Kickoff 15 Jan 2026, 10:00. Launch 31 Jul 2026, 18:30.

calendar: 6 months, 16 days, 8 hours, 30 minutes metric: 197 days 8.5 h = 4,736.5 hours = 284,190 minutes

An invoice quoting “6.5 months” and one quoting “4,736 hours” describe the same interval — but at an hourly rate they will not bill the same, because a “month” has no fixed hour count.

§2The gotchas

Months are not portable units

“3 months” spans 89–92 days depending on where it starts. Contracts that bill by month but measure by day (or vice versa) create real disputes — pick one unit and write it down.

Inclusive or exclusive ends?

Hotel nights, prorated rent and SLA clocks differ on whether the final day counts. This page measures moment-to-moment (exclusive). If your contract counts both end days, add one day.

DST can add or eat an hour

Across a daylight-saving switch, a “9 am to 9 am” day is 23 or 25 hours. India doesn't observe DST, but durations spanning US/EU timestamps do — measure in UTC when it matters.

§3Related

Whole days only? Day counter. Clock arithmetic? Time calculator.