utility calculator
Add, subtract, and convert time durations.
Save this page to sum timesheets, calculate flight durations, or track total activity hours.
Result
3h 55m
Formula
Total minutes = first duration +/- second durationHours and minutes are converted into minutes first, then added or subtracted before the result is converted back to hours and minutes.
Step by step
Example
2 hours 15 minutes plus 1 hour 40 minutes equals 3 hours 55 minutes.
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Summary
Calculated Duration
3h 55m
Total Minutes
235
Decimal Hours equivalent
3.92
D3 visualization
Compare Duration 1, Duration 2, and calculated total in minutes.
D3 visualization
Compare duration equivalents in decimal hours.
Guide
Time arithmetic is unique because hours and minutes use a base-60 scale rather than a decimal base-10 scale. Adding or subtracting durations requires converting values into total minutes first, performing the math, and converting back to hours and minutes.
This tool calculates the result and also displays the decimal hours value (e.g., 1 hour 30 minutes becomes 1.50 decimal hours) which is useful for billing, timesheet entry, and payroll processing.
Sexagesimal system
A numeral system with sixty as its physical base, used to measure time and angles.
Decimal hours
A representation of hours and minutes as a single decimal value, where minutes are written as a fraction of 60.
Divide the number of minutes by 60. For example, 45 minutes divided by 60 equals 0.75 decimal hours.
The calculator clamps the subtraction result at zero so durations never become negative, representing a zero time difference.