Time Calculator
Add, subtract, or convert time between hours, minutes, seconds, and days.
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Time Calculator
Use the formula and worked example below to calculate manually.
Overview
The time calculator lets you add or subtract hours, minutes, and seconds; convert between time units (hours, minutes, seconds, days); and calculate the duration between two specific times or dates.
How to use this calculator
- Choose a mode: Add/Subtract time, Convert units, or Duration between two times.
- Enter the time values in the appropriate fields.
- The calculator shows the result in hours, minutes, and seconds.
Understanding the inputs & results
Duration
The elapsed time between a start and end time.
Time addition
Adding two or more time values. E.g., 2h 45m + 1h 30m = 4h 15m.
Time subtraction
Finding the difference between two times. E.g., 10:30 AM − 7:45 AM = 2h 45m.
The formula
Time conversion
1 day = 24 hrs = 1,440 min = 86,400 sec
Convert any time unit by multiplying or dividing by the appropriate factor. For addition, convert everything to seconds, add, then convert back.
Worked example
Add 3h 45m and 2h 30m.
- Convert to minutes: 225 min + 150 min = 375 min.
- 375 min = 6 hours 15 minutes.
✓ 3h 45m + 2h 30m = 6h 15m.