# Time Duration Calculator

URL: https://speedycalculator.com/calculators/everyday-life/time-duration/
Last updated: 2026-10-25

> The time duration calculator finds the length of time between a start and end time – even across midnight – minus any breaks, in hours and minutes, decimal hours and total minutes.

## Inputs

- Start time
- End time
- Breaks (min)

## Results

- Elapsed time
- Duration
- Decimal hours
- Total minutes
- Start (12-hour clock)
- End (12-hour clock)
- Share of a day

## Formula

```
Duration = end time − start time (+ 24 h if the end is past midnight) − breaks
Decimal hours = hours + minutes ÷ 60
```

## Explanation

Working out a duration from clock times is easy to get wrong when it crosses noon or midnight, or when you mix minutes with decimal hours (7 h 30 min = 7.5 h, not 7.3 h). This calculator handles both 12- and 24-hour clocks – just pick the times.

### How to use the Time Duration Calculator

- **Start time**
- **End time**
- **Breaks**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Pick the start and end times and enter any break.

### Tips

- Check whether the end date should be included – event durations usually include it, elapsed time does not.
- Months have 28–31 days, so "one month" is counted by calendar date, not as 30 days.
- Use 24-hour time or set AM/PM carefully when entering clock times.
- Time zones and daylight-saving changes are not applied unless the calculator says so.

### Common mistakes to avoid

- Counting a 30-day month when a calendar month is meant (or the reverse).
- Forgetting leap years when counting days across February.
- Mixing decimal hours (7.5 h) with clock time (7:30).

### Inputs explained

FieldWhat to enterStart timeA clock time (hours and minutes)End timeA clock time (hours and minutes)BreaksIn min

### What each result means

- **Elapsed time** = mod([End time] - [Start time], 24)
- **Duration** = [Elapsed time] - [Breaks]÷60
- **Decimal hours** = [Duration]
- **Total minutes** = [Duration]×60
- **Share of a day** = [Duration]÷24×100

## Worked example

Inputs — Start time: 09:15; End time: 17:45; Breaks: 30 min.

Results — Elapsed time = 8 h 30 min; **Duration = 8 h 0 min**; Decimal hours = 8; Total minutes = 480; Start (12-hour clock) = 9:15 AM; End (12-hour clock) = 5:45 PM; Share of a day = 33.3 %.

## FAQ

**How do I calculate time between two times?**
Subtract the start from the end; if the result is negative, add 24 hours.

**How many hours from 9:15 am to 5:45 pm?**
8 h 30 min, or 8.5 hours.

**How do I convert minutes to decimal hours?**
Divide by 60 – 45 minutes is 0.75 h.

**What formula does the Time Duration Calculator use?**
Duration = end time − start time (+ 24 h if the end is past midnight) − breaks.