Time Calculator
Type each time as hours:minutes:seconds, choose add or subtract, and add as many rows as you need. The total is shown as hh:mm:ss with hours that keep counting past 24, plus decimal hours, total minutes and total seconds. To apply a total to a time of day, use the add time calculator.
Last updated November 4, 2026
Result
4:16:05
| Measure | Value |
|---|---|
| Hours, minutes, seconds | 4 h 16 m 5 s |
| Decimal hours | 4.27 |
| Total minutes | 256 |
| Total seconds | 15,365 |
Show the work
Formula: total seconds = sum of (hours × 3,600 + minutes × 60 + seconds), adding or subtracting each row
- Row 1: add 2:30:15 = 9,015 seconds.
- Row 2: add 1:45:50 = 6,350 seconds.
- Running total (adds positive, subtracts negative): 15,365 seconds.
- Convert 15,365 seconds: 4:16:05 (hours : minutes : seconds).
- Decimal hours: 15,365 ÷ 3,600 = 4.27.
Result: 4:16:05
How times are added and subtracted
seconds = hours × 3,600 + minutes × 60 + seconds
total = sum of added rows - sum of subtracted rows
Each row is converted to seconds, so there is no carrying to get wrong. Added rows count as positive and subtracted rows as negative, and the signed total is converted back to hours, minutes and seconds by dividing by 3,600 and 60 and keeping the remainders.
Decimal hours are the total seconds divided by 3,600, rounded to two places. If the subtractions are larger than the additions, the answer is shown with a minus sign in front of the magnitude.
See how we calculate for the formulas, sources and review schedule behind every calculator.
Totals beyond 24 hours
This page keeps hours cumulative: 23:59:59 plus 0:00:01 plus 6:30 is 30:30:00, not a time of day. Use it for lap times, track lengths, video runtimes and shift lists. Minutes and seconds must be 0 to 59, so 1:75 is rejected.
How to use the Time Calculator
- Enter the first time as H:MM or H:MM:SS, such as 2:30:15.
- Pick Add or Subtract for each row and use Add another time for more rows.
- Read the total as hh:mm:ss, decimal hours, minutes and seconds.
- Use Show the work to see each row in seconds, then Copy, Print or Share.
Worked example
Adding 2:30:15 and 1:45:50 gives 9,015 + 6,350 = 15,365 seconds, which is 4:16:05 or 4.27 decimal hours.
| Rows | Total | Decimal hours |
|---|---|---|
| + 2:30:15 + 1:45:50 | 4:16:05 | 4.27 |
| + 10:00 - 2:15:30 | 7:44:30 | 7.74 |
| + 23:59:59 + 0:00:01 + 6:30 | 30:30:00 | 30.5 |
| + 1:00 - 1:30 | -0:30:00 | -0.5 |
Frequently asked questions
What format should I type the times in?
Use H:MM or H:MM:SS, such as 2:30 or 2:30:15. Hours can be any whole number, and minutes and seconds must be 0 to 59.
How is this different from the add time calculator?
This page takes clock-style hh:mm:ss values and reports cumulative hours. The add time calculator takes days, hours, minutes and seconds in separate boxes and can apply the total to a time of day.
What happens when the result is negative?
The magnitude is shown with a minus sign, so 1:00 minus 1:30 is -0:30:00. Decimal hours and minutes carry the sign as well.
Can I get the total in decimal hours for a timesheet?
Yes. Decimal hours appear in the results, rounded to two places. For a whole week with breaks and overtime, use the timesheet calculator.