Hours Calculator
Work out the hours and minutes between any two times — breaks and overnight shifts included.
Enter when you started and when you finished, subtract any break, and this calculator returns the exact duration in hours and minutes — plus the decimal hours most timesheets and payroll systems expect. It works for a single shift, a study session, or any block of time, including ones that run past midnight.
How this calculation works
- 01Convert the start and end times into minutes from midnight.
- 02If the end time is earlier than the start time, add 24 hours — the shift crossed midnight.
- 03Subtract the start from the end to get the gross duration in minutes.
- 04Subtract any unpaid break minutes to get the net worked time.
- 05Format the result as HH:MM, and divide minutes by 60 for decimal hours.
- —Overnight shifts (e.g. 22:00 → 06:00) are handled automatically by rolling the end time forward a day.
- —Breaks are treated as unpaid and subtracted from the total — set it to 0 if your break is paid.
- —Decimal hours round to two places (7h 30m = 7.50), which is what most payroll exports use.
- —This is a wall-clock calculation: it does not account for timezone changes or daylight-saving transitions within the shift.
Worked examples
09:00 to 17:30 with a 30-minute lunch break
8h 00m worked (8.00 decimal hours)
22:00 to 06:15 overnight, no break
8h 15m worked (8.25 decimal hours)
13:45 to 16:05, no break
2h 20m worked (2.33 decimal hours)
Frequently asked questions
- How do I calculate hours worked between two times?
- Subtract the start time from the end time, then subtract any unpaid break. For example, 9:00 to 17:30 is 8.5 hours; take off a 30-minute lunch and you have 8 hours. This calculator does that automatically and also shows the decimal-hours figure.
- Does it handle shifts that go past midnight?
- Yes. If your end time is earlier in the day than your start time — like 22:00 to 06:00 — the calculator assumes the shift crossed midnight and adds the extra day, giving you 8 hours rather than a negative number.
- What are decimal hours and why do I need them?
- Decimal hours express minutes as a fraction of an hour (30 minutes = 0.5), so 7 hours 30 minutes becomes 7.5. Most payroll and invoicing systems multiply an hourly rate by decimal hours, which is why the calculator shows both formats.
- Is there a way to track this automatically instead of calculating it each time?
- Yes, and skipping the maths is the whole point of InstaClock. Instead of noting start and end times by hand, you start a timer (or log a block after the fact) and InstaClock keeps the running totals, weekly breakdowns, and visual reports for you.
Stop calculating. Start tracking.
InstaClock keeps your hours, weekly totals, and visual reports running automatically — no start-and-end-time arithmetic required.
Free to start · No card required