Time Duration Calculator.

Calculate the duration between two times, or add and subtract hours and minutes from a start time. Handles overnight spans.

Duration
Total minutes
Decimal hours

Work out how many hours and minutes there are between two times — including shifts that cross midnight — or add and subtract hours and minutes from a starting time. You'll see the duration in hours and minutes, total minutes, and decimal hours, which is exactly what you need for timesheets, billing, travel planning and shift work.

How to use

Pick a mode: 'Time between' calculates the gap between a start and end time (tick 'Ends next day' if the span crosses midnight); 'Add / subtract' applies hours and minutes to a start time, with negative values counting backwards. Results update as you type.

Examples

09:15 → 17:30 8h 15m · 495 minutes · 8.25 decimal hours
22:00 → 06:00 (next day) 8h 0m · 480 minutes · 8.00 decimal hours
08:30 plus 6h 45m 15:15

FAQ

How do I calculate time that crosses midnight?

Enter the start time as normal, then tick 'Ends next day'. The calculator adds 24 hours to the end time, so 22:00 to 06:00 correctly returns 8 hours instead of a negative result.

What are decimal hours?

Decimal hours express the duration as a single number — 8 hours 15 minutes becomes 8.25. Payroll and billing systems usually want decimal hours, while people prefer hours and minutes.

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Privacy and data handling

This tool runs entirely in your browser. Nothing you type or paste is sent to any server — all processing happens locally on your device.