Free · Everyday planning calculators

Clock Components and Decimal Hours

Convert elapsed hours, minutes and seconds into decimal hours, minutes and seconds, or express decimal time in components.

  • Formula & worked example
  • Private in your browser
  • No signup
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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

One hour and thirty minutes is 1.5 hours, 90 minutes or 5400 seconds.

Decimal hours = hours + minutes/60 + seconds/3600

Worked example

Enter these known values and leave the other values blank.

Mode
Hours to decimal
Hours (hh)
1
Minutes (mm)
30
Seconds (ss)
0
Hours
1.5 hrs
Minutes
90 min
Seconds
5400 sec

Assumptions and limitations

  • These are elapsed-duration conversions. Decimal 1.5 hours means 1 hour 30 minutes, not 1 hour 50 minutes. The component controls do not represent dated clock instants.

Common questions

How should I interpret this result?

These are elapsed-duration conversions. Decimal 1.5 hours means 1 hour 30 minutes, not 1 hour 50 minutes. The component controls do not represent dated clock instants.

Can I solve a missing input?

Clear the value you want to find, enter compatible known values, and check the displayed units. Some choices and one-way outputs cannot be solved backward.

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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