Time Duration Calculator

Find the hours and minutes between two times, even overnight or across dates. The answer also comes in decimal hours and total minutes.

Time conversion cheat sheet

HH:MM describes a duration as hours and minutes. Decimal hours describe the same duration as a decimal number of hours. The calculator shows decimal hours to two decimal places; the exact duration and total minutes are unchanged. One minute is 1/60 hour, so 5 minutes is approximately 0.08 hours.

Values marked ≈ are rounded to two decimal places. The whole-minute durations in this table have exact total minutes. For intervals that include seconds, total minutes may be rounded; total seconds remain exact. Use total seconds when adding short intervals.

How to calculate the time between two times

1. Subtract the start time from the end time.
2. If the end has fewer minutes than the start, borrow 60 minutes from one hour.
3. If the end clock time is earlier than the start, the interval crosses midnight: in Time only, select Next day +1; in Date & time, enter the actual start and end dates.

Both modes work from the same total seconds; the exact duration, decimal hours and total minutes all come from that total.

Examples you can reproduce

Try the interactive examples above, or enter these values yourself. All clock times below use 24-hour input.

1. Same day

   Choose Time only. Enter 09:15 → 17:40.

   Result: 8 hours 25 minutes; ≈ 8.42 decimal hours; 505 total minutes.

2. Overnight

   Choose Time only. Enter 23:30 → 01:15 and select Next day +1 explicitly; the calculator never changes this rule for you.

   Result: 1 hour 45 minutes; 1.75 decimal hours; 105 total minutes.

3. Same start and end

   Choose Time only. Enter 09:00 → 09:00.

   Same day selected: 0 hours; 0.00 decimal hours; 0 total minutes.

   Next day +1 selected: 24 hours; 24.00 decimal hours; 1,440 total minutes (86,400 seconds).

4. Seconds precision

   Choose Date & time and turn on Include seconds. Enter 2026-10-24 23:59:59 → 2026-10-25 00:00:00.

   Result: 1 second; 1 total second; ≈ 0.02 total minutes; ≈ 0.00 decimal hours. The 0.00 is a two-decimal display, not an empty interval. Use exact seconds when adding short intervals.

What it does not do

It reads the times as they appear on a clock and does not apply time zones or daylight-saving changes. If a clock change falls between your two times, the real elapsed time differs by that change, usually one hour. Dates can be anywhere from year 1 to year 9999, and every year uses the current leap-year rule.

Which mode should I choose?

Use Time only when the day boundary is explicit: Same day or Next day +1. Use Date & time when the actual dates matter or the span can cover several days. Both modes use the same clock arithmetic; only the way the day boundary is chosen differs.