Hours Calculator
Add or subtract hours and minutes with error-free arithmetic. Use the two-interval tool or tally multiple work sessions with the running accumulator.
Time Calculator (Add & Subtract)
Perform direct addition or subtraction on hours and minutes
Running Hours Accumulator
Add multiple shifts or tasks together
Calculation Result
Time Arithmetic: Add minutes first; whenever minutes reach 60 or more, convert 60 minutes into 1 hour.
For example: 3 hours 45 minutes + 2 hours 30 minutes = 5 hours 75 minutes. Regrouping 75 minutes gives 6 hours and 15 minutes (or 6.25 decimal hours). Subtracting works similarly by borrowing 60 minutes from whole hours when needed.
Understanding Time Addition & Subtraction
Because time uses a sexagesimal (base-60) system for minutes and seconds rather than standard base-10 decimals, standard calculators produce common arithmetic errors when adding times.
For example, adding 3.45 and 2.30 on a regular calculator yields 5.75, but 3 hours 45 minutes plus 2 hours 30 minutes is actually 6 hours and 15 minutes (or 6.25 decimal hours). Our tool converts all inputs into total minutes internally, performs exact integer math, and converts back to avoid rounding discrepancies.