Crunch Time Duration Calculator
Find the time between two clock times — even across midnight — or add and subtract durations for timesheets, shifts, and projects.
Time between two times
| Total minutes | — |
| Decimal hours | — |
Add / subtract durations
How it works
Between-times math converts both clock times to minutes since midnight; if the end time is earlier than the start, a full day (1,440 minutes) is added — that handles overnight shifts automatically. Duration arithmetic works in total minutes and converts back to hours and minutes.
Formula & worked example
Formula: Both times are converted to minutes since midnight (hours × 60 + minutes) and subtracted; if the end time is earlier than the start, 1,440 minutes (24 hours) are added so overnight spans work. Durations can also be added to and subtracted from each other directly.
Worked example: From 9:15 AM to 5:45 PM: 1,065 − 555 = 510 minutes, which is 8h 30m — 8.50 hours in decimal form.
Frequently asked questions
Does it handle overnight shifts?
Yes. A shift from 22:00 to 06:00 correctly returns 8 hours — end times earlier than the start are treated as the next day.
What are decimal hours for?
Payroll and billing usually use decimal hours: 8 hours 15 minutes = 8.25 hours. The converter gives you both formats.
Can I add more than two durations?
Add the first two, then use the result as Duration 1 with the next duration — or tally weekly hours in our freelance rate calculator.
⏱️ Billing by the hour?
Turn those hours into a rate with the freelance hourly rate calculator, or convert wages with the hourly-to-salary converter.