Decimal Hours Calculator
Convert hours and minutes to decimal hours, or convert a decimal-hour value back to hours and minutes.
Convert hours and minutes to decimal hours
Decimal hours express a duration in base 10 instead of base 60. Keep the whole hours, divide the minute portion by 60, then add the two values.
decimal hours = hours + minutes ÷ 60
For 8 hr 30 min, 30 ÷ 60 = 0.50, so the result is 8.50 hours.
Convert decimal hours back to hours and minutes
Keep the whole-number hour portion and multiply the decimal fraction by 60. The calculator rounds to the nearest whole minute when the decimal cannot map exactly to a whole minute.
minutes = decimal fraction × 60
Why 8.30 is not 8 hours 30 minutes
A decimal fraction of .30 means thirty hundredths of an hour. Multiplying .30 by 60 gives 18 minutes, so 8.30 decimal hours equals 8 hr 18 min.
Rounding
When several durations must be added, keeping exact minutes until the final conversion can reduce differences caused by rounding each daily decimal first.