The Decimal Hours Formula
The formula
Decimal = H + (M ÷ 60)
With seconds: Decimal = H + (M ÷ 60) + (S ÷ 3600)
Understanding the Formula
The decimal hours formula converts time from the base-60 system (hours and minutes) to base-10 (decimal). Since there are 60 minutes in an hour, dividing minutes by 60 gives you the fractional hour equivalent.
Why divide by 60?
There are 60 minutes in one hour. Dividing minutes by 60 converts them to a fraction of an hour. 30 minutes = 30/60 = 0.50 of an hour. 15 minutes = 15/60 = 0.25 of an hour.
Worked Examples
The Reverse Formula
To convert decimal hours back to hours and minutes:
Hours = whole number part (floor)
Minutes = decimal part × 60
Example: 5.70 → Hours = 5, Minutes = 0.70 × 60 = 42
Result: 5 hours 42 minutes
Formula in Different Tools
Excel / Google Sheets
=A1*24
(if A1 contains a time value)
Python
decimal = hours + minutes / 60
JavaScript
const decimal = hours + minutes / 60;