Free Online Time Duration Calculator
Runs 100% in your browser — your times never leave your device.
Duration between two times
Timesheet total
Add one row per work block (e.g. morning and afternoon sessions).
About this time duration calculator
Subtracting times is easy until midnight gets involved. "23:00 to 07:00" breaks naive subtraction, but it is a perfectly normal night shift — 8 hours. This calculator treats an end time earlier than the start time as the next day, so overnight work just works.
The timesheet mode totals split days — morning and afternoon sessions, or multiple gigs in one day — into one total, shown both as hours-and-minutes and as decimal hours (8.5h), the format payroll systems expect.
Worked examples
A standard day. 09:00 to 17:30 is 8 hours 30 minutes — 510 minutes, or 8.5 decimal hours. The first box on this page gives all three figures.
A night shift. 22:00 to 06:30: the end time is earlier than the start, so it counts as the next day — 8 hours 30 minutes again. No date-picking needed; the overnight rule handles it.
A split day in the timesheet. Morning 08:30–12:15 (3h 45m) plus afternoon 13:00–17:45 (4h 45m): the timesheet totals 8 hours 30 minutes — 510 minutes, 8.5 decimal hours, ready for a payroll entry.
Minutes to decimal hours. Divide minutes by 60: 7 hours 25 minutes is 7 + 25 ÷ 60 = 7.42 hours, rounded to two places — the precision payroll systems use. The timesheet total shows this figure automatically.
Who uses this calculator
Shift workers log their hours to check payslips; freelancers turn clock times into billable hours; managers total a team's daily rows into a weekly figure. If you ever do timesheets by hand — especially overnight or split shifts — this removes the mental subtraction and the midnight mistakes that come with it.
How to use
- Enter a start and end time (24-hour clock) and press Calculate duration.
- For a whole day, add rows in Timesheet total — one per work block — and press Total timesheet.
- Identical start and end times count as zero duration; see the FAQ for a 24-hour span.
Limitations
- Breaks are not auto-detected — split your day into rows around unpaid breaks.
- An end time before the start time always means "next day"; the tool cannot represent spans longer than 24 hours in a single row.
- Decimal hours are rounded to 2 places.
- Times resolve to the minute — seconds are not supported.
- Daylight-saving clock changes are ignored; a shift crossing one is measured as if the clock did not move.
Frequently asked questions
How do overnight shifts work?
If the end time is earlier than the start time, the calculator treats the end as the next day. So 23:00 to 07:00 is an 8-hour overnight shift.
Why do identical start and end times show zero?
09:00 to 09:00 is treated as zero duration, not 24 hours. If you need a full 24-hour span, enter times one minute apart (e.g. 09:00 to 08:59) or use two timesheet rows.
How does the timesheet mode work?
Add one row per work block with a start and end time — for example morning and afternoon sessions — and the calculator totals them into hours and minutes plus a decimal-hours figure for payroll.
How do I convert minutes to decimal hours?
Divide minutes by 60: 90 minutes is 1.5 hours. The timesheet total shows both formats.
Is my data uploaded anywhere?
No. The calculator runs 100% in your browser with JavaScript. Your times never leave your device, are never stored, and never sent to any server.
How do I calculate hours worked with an unpaid lunch break?
Enter the day as two rows: for example 09:00–12:30 and 13:30–17:30. The timesheet totals only the work blocks and ignores the break in between.
How do I add up a full week of shifts?
Add one row per shift per day with the + Add row button — Monday 09:00–17:00, Tuesday 09:00–17:00, and so on — then press Total timesheet for the week's hours in minutes and decimal hours.
What is 7 hours 25 minutes as decimal hours?
7.42 hours: 25 ÷ 60 = 0.4167, rounded to two places — the precision payroll systems use. The timesheet total shows this figure automatically.
Can I time something longer than 24 hours?
Not in one row — a row always represents a single clock-to-clock span under 24 hours. For multi-day totals, add one row per day (or per work block) in the timesheet and let it add them up.