Add or subtract time durations with hours, minutes and seconds precision. Convert between HH:MM:SS, decimal hours, total minutes and total seconds — ideal for media editing, sports timing and billing.
Toggle between Add (combine multiple durations) or Subtract (remove a duration from another). For conversion only, enter a single duration and click Calculate to get all equivalent formats at once.
Type hours, minutes and seconds for each entry. Add as many rows as you need using the + button. Entries are validated as you type — if you enter 75 seconds the tool automatically carries over to minutes. Supports durations over 99 hours.
The result displays simultaneously as: HH:MM:SS, decimal hours (e.g. 2.517 hrs), total minutes, total seconds, and a plain language description ("2 hours 31 minutes 2 seconds"). Click any value to copy it instantly.
A clock time is a point in the day (e.g. 14:30 = 2:30 PM). A time duration is a length of elapsed time (e.g. 2 hours 30 minutes). This calculator works with durations — you can add, subtract and convert them regardless of what time of day they started. For clock time arithmetic (start + duration = end time), use the Hours Calculator.
Enter the first clip duration in HH:MM:SS format, click the + button to add a second row, and enter the second clip duration. The total at the bottom gives you the combined runtime. This is widely used in video editing, podcast production and media post-production to calculate total programme length.
Enter the duration (e.g. 3 hours 45 minutes) and the decimal conversion is shown automatically: 3h 45m = 3.75 decimal hours. The formula is: hours + (minutes ÷ 60) + (seconds ÷ 3600). Our tool does this instantly for all entered durations.
Total seconds is used in programming and database contexts (Unix timestamps, video frame calculations, audio sample alignment), sports timing (a swimmer 200m time of 1:47.32 = 107.32 seconds), and scientific data where a single numeric value is more useful than a broken-down format.
If the subtracted duration is larger than the base duration, the result will be shown as a negative time. For example, 1h 00m 00s minus 1h 30m 00s = -0h 30m 00s. The result clearly marks negative durations so you can see that the subtracted amount exceeds the base.
Enter the decimal hours as hours (e.g. 2.75 hours = 2 hours and 0 minutes and 0 seconds as the input, then adjust minutes to 45). Alternatively, the reverse is automatic: type 2 in hours, 45 in minutes, and the decimal equivalent 2.75 is shown instantly. The conversion is bidirectional.
There is no practical upper limit — the calculator correctly handles durations of thousands of hours. For example, adding up project hours across months will give accurate totals without any overflow. Durations exceeding 99 hours are displayed as e.g. 142:30:00, not rolling over at 24 hours.
Yes — enter the race duration in HH:MM:SS for each athlete. Use subtract mode to calculate time behind the leader. Convert to total seconds for ranking, pace calculation and data export. Swim splits, running splits and cycling stage times are all common use cases.
The Time Duration Calculator is a pure duration arithmetic tool — it works with HH:MM:SS values representing elapsed time and converts between formats. The Time Card Calculator is a payroll tool that works with clock-in/out times to calculate work hours, break deductions, overtime and gross pay. They serve complementary purposes.
You can enter durations in multiple formats: HH:MM:SS (e.g. 1:30:00), H:MM (e.g. 1:30), decimal hours (e.g. 1.5), or plain numbers in each field (1 hour, 30 minutes, 0 seconds). The tool parses all standard formats and normalises entries that exceed their field range (e.g. 90 seconds becomes 1 minute 30 seconds).
