Hours and minutes--
Decimal hours--
Time Duration Calculator
Use this time duration calculator to measure elapsed time for shifts, projects, trips, events, and overnight time spans.
Updated May 2026No signup requiredBuilt for mobile
Calculator
How to use this calculator
- Enter your values in the calculator fields.
- Check that the units and percent formats match what the label asks for.
- Click Calculate to update the result.
- Use Reset Calculator to restore the starting example.
Formula or calculation method
Elapsed time = end date and time - start date and time.
Decimal hours = total minutes / 60.
If the end time is earlier and no end date is provided, the calculator treats it as overnight.
Worked example
From 9:15 AM to 5:45 PM is 8 hours 30 minutes, or 8.5 decimal hours.
Practical planning tips
- Elapsed time
- Shift lengths
- Project tracking
- Travel time
- Event schedules
Common mistakes to avoid
- Forgetting overnight spans
- Mixing decimal hours with hours and minutes
- Leaving the date blank when a span crosses multiple days
FAQ
Time Duration Calculator questions
Is this calculator exact?
It is a practical estimate based on the values you enter. Verify important decisions with the official source, lender, school, product label, or professional guidance when needed.
Why did I get an error?
The calculator checks for blank fields, invalid numbers, impossible negative values, and divide-by-zero situations. Review the message and adjust the input.
Can I use this calculator on my phone?
Yes. The inputs, buttons, and result cards are built to work on mobile screens.
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