Time Duration Calculator Guide: Formula & Worked Example
Short answer
Hours and minutes between two times of day. In the fixed example below, duration is 8 h 30 min. Your answer depends on the inputs and assumptions you choose.
Formula
Result = Time Duration Calculator calculation using start hour (0–23), start minute, end hour (0–23), end minute
The inputs are start hour (0–23), start minute, end hour (0–23), end minute. Use the input scale shown beside each field and keep time periods and units consistent. Only round the final result for display.
Worked example
- Start hour (0–23)
- 9
- Start minute
- 15
- End hour (0–23)
- 17
- End minute
- 45
- Duration: 8 h 30 min
- Total minutes: 510
- Decimal hours: 8.5
Understanding the result
Hours and minutes between two times of day. Start with the base example, then replace each value with the figure that matches your situation.
Start hour (0–23)
The example uses 9 for start hour (0–23). This is an illustration, not a recommended value. Keep the unit and time period shown by the field.
Start minute
The example uses 15 for start minute. This is an illustration, not a recommended value. Keep the unit and time period shown by the field.
End hour (0–23)
The example uses 17 for end hour (0–23). This is an illustration, not a recommended value. Keep the unit and time period shown by the field.
End minute
The example uses 45 for end minute. This is an illustration, not a recommended value. Keep the unit and time period shown by the field.
What the comparison means
The comparison changes only start hour (0–23), keeping every other example input fixed. This isolates that input's effect on the primary result. It does not predict future outcomes.
Check units, date boundaries and rounding before using the answer in a report or a practical measurement.
Comparison
| Scenario | Input | Result |
|---|---|---|
| Lower input | Start hour (0–23): 7.2 | Duration: 10 h 18 min |
| Base example | Start hour (0–23): 9 | Duration: 8 h 30 min |
| Higher input | Start hour (0–23): 10.8 | Duration: 6 h 42 min |
Common mistakes
- Using the wrong units for start hour (0–23).
- Comparing results while changing more than one input at a time.
- Check units, date boundaries and rounding before using the answer in a report or a practical measurement.
Checklist
- Confirm start hour (0–23).
- Confirm start minute.
- Confirm end hour (0–23).
- Confirm end minute.
- Check the result against your source or provider.
Calculators Percentage Editorial Team
Calculator guides from the Calculators Percentage team. These introductory examples are educational, not professional advice.
Last reviewed:
Check units, date boundaries and rounding before using the answer in a report or a practical measurement.