Free · Everyday calculations

Minutes Between Two Clock Offsets

Subtract a start time from an end time using hours, minutes and seconds, with editable duration units.

  • Formula & worked example
  • Private in your browser
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

From 09:15:00 to 11:45:00 is 150 minutes, or two hours thirty minutes. Both entries are measured from the same time origin.

Duration = end offset − start offset

Worked example

Enter these known values and leave the other values blank.

Start time / offset
9:15:0 hrs / min / sec
End time / offset
11:45:0 hrs / min / sec
Elapsed duration
150 min

Assumptions and limitations

  • Enter compound times as hours:minutes:seconds. Both offsets must use the same origin, and the end must be equal to or later than the start.
  • An earlier clock reading does not automatically roll into the next day. For 23:30 to the next day’s 01:00, enter 23:30:0 and 25:0:0.
  • This is elapsed-offset subtraction without calendar dates, time zones, daylight-saving changes or leap seconds. Equal start and end offsets produce zero duration.

Common questions

How do I calculate an overnight interval?

Express the next day’s end using hours beyond 24. From 23:30:0 to 25:0:0 is 90 minutes; entering 1:0:0 as the end would be earlier than the start.

Can I find the end from a duration?

Yes. Enter the start and the duration, leaving the end blank. A start of 9:15:0 plus 150 minutes gives an end of 11:45:0.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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