Time Duration Calculator
Calculate the exact duration between two points in time.
Set Start & End
What is the Time Duration Calculator?
The Time Duration Calculator performs arithmetic on lengths of time rather than clock times. It allows you to add or subtract arbitrary amounts of hours, minutes, and seconds together, which is incredibly useful for video editing and audio production.
How It Works (Algorithm)
When adding time, standard math fails (e.g., 50 minutes + 20 minutes is not 70 minutes, it is 1 hour and 10 minutes). The tool converts all inputs into total seconds, performs the addition or subtraction, and uses modulo division to extract the proper base-60 hours and minutes.
$$ \text{Minutes} = \left( \frac{\text{Total Seconds}}{60} \right) \pmod{60} $$
Modulo division is required to extract rolled-over time values.
How to Use It
Enter your first duration (e.g., 2 hours, 45 minutes). Select Add or Subtract. Enter your second duration (e.g., 1 hour, 30 minutes). The tool will output the perfectly rolled-over resulting time (e.g., 4 hours, 15 minutes).