# Time Duration Calculator

> Find the time between two clock times, including overnight spans, or between two dates and times, in days, hours, minutes and decimal hours.

Category: Date, time & lifestyle · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/time-duration-calculator

Enter a start and an end time to get the elapsed time. If the end time is earlier than the start and no dates are given, it is taken as the next day, as for a night shift.

Also called: Elapsed time calculator, Hours between times calculator.

## Inputs
- Start date (optional) (default ; optional)
- Start time (default 09:15)
- End date (optional) (default ; optional)
- End time (default 17:45)

## Results
- Duration
- In decimal hours
- In minutes
- In seconds
- As hh:mm

## Formula

```
Duration = (End date − Start date) × 24 h + (End time − Start time);  without dates, add 24 h when the end time is earlier than the start;  Decimal hours = Hours + Minutes ÷ 60
```

Where:
- Dates: calendar dates; leap days are counted
- Times: 24-hour clock times

## Worked example
1. 17:45 − 09:15 = 8 hours and 30 minutes.
2. Decimal hours = 8 + 30 ÷ 60 = 8.5.
3. In minutes: 8 × 60 + 30 = 510.

**Result:** From 9:15 to 17:45 is 8 hours 30 minutes, or 8.5 hours.

## What the result means

Decimal hours are what timesheets and payroll multiply by an hourly rate: 8 h 30 min is 8.5 hours, not 8.30.

## Assumptions and limits
- Clock times are in the same time zone.
- Daylight-saving changes are not applied: a span across a clock change will be an hour off.
- Breaks are not deducted.

## Questions

### How do I convert minutes to decimal hours?

Divide by 60. 15 min = 0.25 h, 30 min = 0.5 h, 45 min = 0.75 h.

### How do I time a night shift?

Enter the start and end times with no dates. If the end is earlier than the start, it is counted as the next morning: 22:30 to 06:15 is 7 h 45 min.

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Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/time-duration-calculator