How this calculator works
Clock-style parts count sixty minutes in an hour and sixty seconds in a minute. Decimal notation instead describes a fraction of the selected unit. The calculator first totals the duration in seconds, then divides by 60 or 3600. Reverse modes split a decimal duration into whole hours, whole minutes and remaining seconds. The steps table makes each contribution visible. The tool handles elapsed time, without dates or timezones.
Formula
Decimal hours = H + M/60 + S/3600. Decimal minutes = 60H + M + S/60. Total seconds = 3600H + 60M + S. To reverse, take whole hours first, then whole minutes from the remaining seconds.
Worked example
1 hour 45 minutes 30 seconds becomes 1.7583333333 decimal hours, 105.5 decimal minutes or 6330 seconds. In reverse, 2.25 decimal hours is 2 hours 15 minutes. A decimal-minute value of 1.5 is 1 minute 30 seconds.
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Frequently asked questions
Is 1.30 hours the same as 1 hour 30 minutes?
No. 1.30 decimal hours is 1 hour 18 minutes. One hour 30 minutes is 1.5 decimal hours.
Can I enter 90 in the clock-style minutes box?
Use 1 hour 30 minutes in parts mode, or choose decimal minutes and enter 90. The separate clock-style minutes field runs from 0 to 59.
Does the calculator round to a payroll increment?
No. It converts the entered duration without applying a payroll rounding rule. Displayed decimals are rounded for readability; numeric outputs retain their calculated precision.
Can I enter fractional seconds?
Yes. Seconds may include a decimal fraction below 60. Hours and minutes in parts mode must be whole numbers.