Time to Decimal Calculator

Convert a clock time or duration in hours, minutes, and seconds into decimal hours using decimal hours = H + M/60 + S/3600 — plus the equivalent in decimal minutes, decimal days, and a payroll-rounded value.

Quick Facts

Formula
Decimal hours = H + M/60 + S/3600
15 min = 0.25 hr, 30 min = 0.50 hr, 6 min = 0.10 hr.
Why it matters
Hourly pay uses base-10 math; clocks use base-60
7:30 (h:m) must become 7.5 before multiplying by an hourly wage.

Your Results

Calculated
Decimal hours
-
H + M/60 + S/3600
Decimal minutes
-
Total time as minutes
Decimal days
-
Decimal hours ÷ 24
Rounded (payroll)
-
Per selected rounding rule

Ready

Enter a time and press Calculate.

Understanding Time to Decimal Conversion

Clock time is written in base 60 — 60 seconds make a minute, 60 minutes make an hour — but arithmetic like payroll, billing, and spreadsheets works in base 10. Converting a duration or clock time into decimal hours lets you multiply directly by an hourly rate, sum up timesheet entries, or plot a duration on a normal number line without the base-60 gotchas.

The formula

For a time expressed as H hours, M minutes, and S seconds, decimal hours are:

Decimal hours = H + M / 60 + S / 3600

The same total, expressed in different units, gives decimal minutes (H × 60 + M + S / 60) and decimal days (decimal hours ÷ 24). All three come from converting everything to a common unit — seconds — and then dividing back up into the unit you need.

Common reference conversions

  • 15 minutes = 0.25 decimal hours (a quarter hour)
  • 30 minutes = 0.50 decimal hours (a half hour)
  • 45 minutes = 0.75 decimal hours
  • 6 minutes = 0.10 decimal hours (a common payroll rounding unit)
  • 1 minute ≈ 0.0167 decimal hours (1/60)

Why payroll systems round

Many employers round clock-in/out punches to the nearest 6 minutes (0.1 hour) or 15 minutes (0.25 hour) before converting to decimal, both to simplify pay calculations and because punches are rarely exact to the second. In the US, the Fair Labor Standards Act permits rounding time to the nearest 5, 6, 10, or 15 minutes as long as the practice does not, over time, consistently work to the employee's disadvantage. Always confirm your organization's documented rounding policy — this calculator offers exact, 0.01, 0.1, and 0.25-hour rounding as common reference options, not a substitute for that policy.

Common uses

  • Converting timesheet punches (e.g., 7 hours 45 minutes worked) into decimal hours for payroll software
  • Billing clients by the decimal hour instead of hours and minutes
  • Converting a stopwatch or lap split into decimal minutes for data analysis
  • Preparing duration data for charts, formulas, or scripts that expect a single decimal number

Frequently Asked Questions

How do I convert time to decimal hours?
Divide the minutes by 60 and the seconds by 3600, then add both to the hours. For example, 7 hours 30 minutes becomes 7 + 30/60 = 7.5 decimal hours. This H + M/60 + S/3600 formula is the standard method used by payroll and timesheet software.
Why do payroll systems use decimal hours instead of minutes?
Decimal hours multiply cleanly by an hourly wage. Paying someone for 7 hours 30 minutes requires converting to 7.5 hours first — treating .30 as 30 hundredths instead of 30/60 of an hour would understate the pay, since 7.30 hours is not the same duration as 7 hours 30 minutes.
What's the difference between 0.1-hour and 0.25-hour rounding?
Rounding to the nearest 0.1 hour rounds to the nearest 6 minutes. Rounding to the nearest 0.25 hour rounds to the nearest 15 minutes, a common payroll convention. Use "Exact" when you need the unrounded value, such as for billing or data analysis.
How accurate are the results?
The conversion is exact arithmetic — decimal hours = H + M/60 + S/3600 — so results are precise to the number of decimal places shown. Any rounding applied is only the rounding rule you selected, not calculation error.

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