How to use this calculator
To make decimal hours, divide the minute component by 60 and add it to the whole hours. For the reverse direction, multiply decimal hours by 60 and round to a whole minute before splitting into hours and remaining minutes.
Formula
Decimal hours = H + M ÷ 60; Total minutes = round(Decimal hours × 60)
Worked example
8 hours 30 minutes equals 8 + 30/60 = 8.5 hours. Conversely, 8.25 hours equals 495 minutes, or 8 hours 15 minutes.
Assumptions and limits
The decimal input is nonnegative. The reverse conversion rounds to the nearest minute; seconds are not retained. The tool accepts up to one million input hours.
Frequently asked questions
Why is 8:30 different from 8.30?
8:30 means 8 hours 30 minutes. 8.30 decimal hours means 8 hours plus 0.30 × 60 = 18 minutes.
Are the results decimal hours or clock time?
Both are shown where useful. Decimal hours divide minutes by 60; a duration such as 7 h 30 min is 7.5 hours.
Are my times uploaded?
No. Calculations run in your browser. Saved inputs remain on this device until reset or cleared in browser site-data settings.
Decimal-to-time results are rounded to the nearest minute, with half minutes rounded up.