Calculator
Hours and time calculator
Add independent intervals, deduct breaks or convert decimal notation. Overnight intervals require an explicit next-day choice. This is time arithmetic, not employment records or elapsed-time measurement across daylight-saving changes.
Calculator
Enter data
Choose a single interval, interval list or time conversion direction. Fields marked with an asterisk are required.
How to use the calculator
- Choose a mode; for each interval enter times, break and the correct ending day.
- Add up to 50 independent rows or convert time. Recalculate after editing.
Calculation details
Formula and calculation method
Net minutes = end + 1440 × next day − start − break. Decimal hours = minutes / 60. Decimal-to-minute conversion rounds to the nearest minute.
Worked example
22:00–06:00 next day with a 30-minute break gives 7 hr 30 min, or 7.5 hours. 7:30 does not mean 7.30 hours.
Limitations
- Rows are independent: overlapping intervals are summed, not merged. No dates, DST, overtime rules or paid-break policies.
- Yes always adds one day, even when the end clock time is later. Equal times give 0 or 24 hours before breaks.
Sources
Engine version: 2.0 (2026-09-23) · Last reviewed: 23 September 2026
Frequently asked questions
Is 1.5 hours 1 hr 50 min?
No. 0.5 × 60 = 30 minutes, so 1.5 hours is 1 hr 30 min.
Does this include daylight-saving changes?
No. These are clock times without dates; real elapsed time requires dates and a time zone.