Time Duration Calculator Calculators
Work out the time between two clock times, across midnight if needed.
Time Duration Calculator is a free online tool that work out the time between two clock times, across midnight if needed. It runs entirely in your web browser using plain JavaScript, so files are processed on your own device and never uploaded to a server. There is no sign-up, no file size limit imposed by the site, no watermark and no paid tier.
- Price
- Free — no account, no quota, no watermark
- Category
- Calculators
- Where it runs
- In your browser, on your device
- Files uploaded
- None
- Technology
- plain JavaScript
- Settings
- 4
- Works offline
- Yes, after the first visit
About Time Duration Calculator
Shifts that cross midnight are handled by adding a day when the end time is earlier than the start — so 22:00 to 06:00 correctly returns eight hours rather than minus sixteen. Decimal hours are given alongside, since that is what payroll systems almost always want.
How to use it
- Enter start time, end time and break (minutes).
- Adjust the remaining 1 setting if the defaults do not fit your case.
The 4 settings
| Setting | What it does | Default |
|---|---|---|
| Start time | Free text. | 09:00 |
| End time | Free text. | 17:30 |
| Break (minutes) | Range 0–600. | 30 |
| Hourly rate (optional) | A numeric value. | 0 |
Under the hood
| Runs on | plain JavaScript — runs the whole thing |
| Controls | Start time, End time, Break (minutes), Hourly rate (optional) |
Questions
Why does my timesheet total differ from the decimal figure?
Rounding. Many payroll systems round each shift to the nearest quarter hour, which accumulates over a month. The decimal figure here is exact.
What are the limits on break (minutes)?
It accepts 0 to 600, starting at 30.
Is the arithmetic exact?
It uses double-precision floating point — about 15 significant figures, far more than the inputs justify. Displayed rounding is cosmetic; the underlying numbers are not rounded between steps, so chained results do not drift.