Add and subtract time
Total several positive and negative durations.
Add and Subtract Time
Combine several duration quantities. Each row can add or subtract time.
How multi-row time arithmetic works
Every row is converted to integer seconds. Subtract rows become negative, all rows are totaled, and the final value is normalized into days, hours, minutes, and seconds.
Examples
1 h 30 min + 2 h 45 min = 4 h 15 min.
5 h − 6 h 20 min = −1 h 20 min.
Boundary cases
Minute or second values above 59 are accepted as duration overflow and normalized. Use the operation selector rather than typing negative field values.
Can the result be negative?
Yes. A leading minus sign means the subtracted durations exceeded the added durations.
Is this for clock times?
No. These are duration quantities. Use the homepage to find the difference between clock times.
Related time tools
Hours and minutes arithmetic
Add or subtract duration quantities with automatic carry and borrow.
Convert decimal hours
Convert both ways and apply optional payroll-style rounding.