Hours & Time Calculator
Time Duration Calculator works out Duration in hours and Duration in minutes from What to calculate, Durations and A two-part duration like 3:45 means. The default figures on this page give duration in hours of 8.0000 h; change any entry and the result, the working and the sources update together.
Your figures
Updates as you typeHow this is worked out
2 steps
- Elapsed = 17:00:00 - 09:00:00 = 8:00:00.
- 480 minutes total = 8 hours (60 s = 1 min, 60 min = 1 h).
Its 10 worked examples are re-run on every release, last on 15 September 2026. What changed
Sources and references
3 sources
What the Time Duration Calculator calculates
Elapsed time between two clock times, including overnight and multi-day spans, adding or subtracting hours, minutes and seconds from a time, totalling a list of durations such as a playlist or a set of videos, halving or splitting a duration, and rescaling a runtime for playback speed.
How to use this Time Duration Calculator
Enter What to calculate, Durations, A two-part duration like 3:45 means and Number of equal parts. Duration in hours updates as you type, and “Use a worked example” loads checked figures you can adjust. Change one figure at a time to see what drives the result.
How the result is worked out
Open “How this is worked out” beside the result for the step-by-step calculation behind Duration in hours, Duration in minutes and Duration in seconds.
The method follows ISO 8601-1:2019, Date and time - Representations for information interchange, clauses 5.3 and 5.5, BIPM SI Brochure, 9th edition, Table 8 (non-SI units accepted for use with the SI) and US Department of Labor, Fact Sheet #22: Hours Worked Under the FLSA.
09:00 to 17:30 is eight and a half hours example
With What to calculate: difference, Start time: 09:00, End time: 17:30, the calculator returns Duration in hours: 8.5, Duration in minutes: 510, Duration in seconds: 30600. This example is checked against an independent source in the test suite.
What you can compare
Change one input at a time to see how it affects Duration in hours, Duration in minutes and Duration in seconds. The inputs you can vary are What to calculate, Durations, A two-part duration like 3:45 means, Number of equal parts, Playback speed and Start time.
Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.
See something wrong? Report a problem with this calculator
Frequently asked questions
What information do I need for the Time Duration Calculator?
You need What to calculate, Durations, A two-part duration like 3:45 means, Number of equal parts, Playback speed, Start time, End time and Start date (optional). The page opens with default figures that give duration in hours of 8.0000 h, so you can see the scale before entering your own.
What does this Time Duration Calculator show?
It shows Duration in hours, Duration in minutes, Duration in seconds, Whole days, Hours part, Minutes part, Seconds part and Duration as h:mm, with the working and any warnings for your entries.
Can I check how the Time Duration Calculator result was calculated?
Yes. The “How this is worked out” section shows the calculation steps, and the sources section identifies the references used for the method.