Time to Decimal Calculator — Convert HH:MM to Decimal Hours
Payroll systems, billing software and spreadsheets often require time in decimal format (e.g. 7.5 hours instead of 7:30). Enter hours, minutes and optional seconds to convert instantly. The calculator also shows total minutes and seconds for completeness.
h
min
sec
Time expressed as a decimal fraction of an hour — used in payroll and billing
- 1
Minutes as decimal hours
30 ÷ 60 = 0.5 - 2
Decimal hours
7 + 0.5 = 7.5000
How does this calculator work?
Divide minutes by 60 and seconds by 3600, then add to whole hours: Decimal = H + M/60 + S/3600. So 7h 30m = 7.5, 7h 45m = 7.75, 1h 15m = 1.25. Used in payroll and billing where software expects a decimal number of hours.
Formula
How this is calculated
Time in HH:MM:SS format uses a base-60 (sexagesimal) system: 60 seconds per minute, 60 minutes per hour. Converting to decimal simply divides each smaller unit by its conversion factor and sums the parts: hours stay as-is, minutes are divided by 60, and seconds are divided by 3600 (60 × 60). For example, 7 hours 45 minutes 30 seconds = 7 + 45/60 + 30/3600 = 7.759 hours (rounded to 3 dp).
Decimal hours are the standard input format for most payroll, project management and billing applications. A common source of confusion is that 8:30 does NOT mean 8.30 hours — it means 8.5 hours (8 hours and half an hour). This calculator makes that conversion explicit and precise.
For reverse conversion (decimal back to HH:MM): multiply the decimal part by 60 to get minutes, then multiply any remaining decimal by 60 for seconds.
Frequently asked questions
Divide the minutes by 60. For example, 45 minutes ÷ 60 = 0.75 hours. Add that to the whole hours: 3 hours 45 minutes = 3.75 hours.
Decimal numbers are easy to multiply by an hourly rate to get pay. 7.5 hours × $20/hr = $150 is a straightforward multiplication; 7:30 × $20/hr requires the extra conversion step. Most payroll software therefore stores time in decimal format internally.
No. 8:30 (8 hours 30 minutes) equals 8.5 decimal hours, not 8.30. The minutes digit is not a decimal — it is a base-60 fraction. This is the most common mistake when entering time in payroll systems.
Also known as
TG we-Calculate Editorial Team. (2026). Time to Decimal Calculator — Convert HH:MM to Decimal Hours [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/time-to-decimal-calculator
TG we-Calculate Editorial Team. "Time to Decimal Calculator — Convert HH:MM to Decimal Hours." TG we-Calculate. 2026. https://we-calculate.com/calculator/time-to-decimal-calculator.
TG we-Calculate Editorial Team, "Time to Decimal Calculator — Convert HH:MM to Decimal Hours," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/time-to-decimal-calculator
@misc{wecalculate_time_to_decimal_calculator, title = {Time to Decimal Calculator — Convert HH:MM to Decimal Hours}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/time-to-decimal-calculator}}, year = {2026}, note = {TG we-Calculate} }
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