Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Duration
8h 30m
Total hours
8.50
Total minutes
510
Psst — share this and help Rex grow
One click, a permanent link with your numbers baked in.
How to use this
- 1Enter start hour.
- 2Enter start minute.
- 3Enter end hour.
- 4Enter end minute.
- 5Read your duration on the right — it updates as you type.
- 6Hit Share to keep the scenario or send it to someone.
About this calculator
Enter start and end times in 24-hour format to get the duration.
Worked example
Using the values the calculator loads with:
Inputs
- Start hour: 9
- Start minute: 0
- End hour: 17
- End minute: 30
Results
- Duration: 8h 30m
- Total hours: 8.5
- Total minutes: 510
What each field means
Inputs
- Start hour
- The start hour used in the calculation. Starts at 9 so you have a working example on load. Accepted range: 0–23.
- Start minute
- The start minute used in the calculation. Starts at 0 so you have a working example on load. Accepted range: 0–59.
- End hour
- The end hour used in the calculation. Starts at 17 so you have a working example on load. Accepted range: 0–23.
- End minute
- The end minute used in the calculation. Starts at 30 so you have a working example on load. Accepted range: 0–59.
Results
- Duration
- Returned as a plain value and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Total hours
- Returned as a decimal number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Total minutes
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How does the time duration calculator work?
Enter start and end times in 24-hour format to get the duration.
What do I need to enter?
4 values: start hour, start minute, end hour, and end minute. Each field starts with a sensible default, so you can change one number at a time and watch the result move.
What does the duration result mean?
It is returned as a plain value and updates live as you edit the inputs, so you can compare two or three versions of a scenario in a few seconds.
Is this calculator free, and do I need an account?
Yes, it's free, and no account is required. Nothing you type is stored on our servers — the maths runs entirely in your browser.
How accurate is the result?
It applies the standard formula exactly, so the arithmetic is precise. Estimates assume standard, average conditions — local rules, pricing, and materials vary.
Who is this tool for?
It's built for anyone doing everyday planning maths — a quick estimate that would otherwise need four browser tabs and a calculator app.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Time Duration Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/time-duration
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/time-duration" target="_blank" rel="noopener">Time Duration Calculator — RevenueLab</a> (2026).</p>
Source: [Time Duration Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/time-duration) (2026).