Calculators / Time calculator
Time calculator
Add or subtract durations without converting every entry yourself.
Durations are lengths of time, not clock times. Negative totals are supported.
Adding and subtracting hours and minutes
A duration such as 2 hours 45 minutes is a quantity of time. Unlike a clock reading, it does not restart after midnight. This calculator combines up to 50 durations and keeps totals above 24 hours.
Minutes per entry = hours × 60 + minutes
Add or subtract those entries, then divide the absolute total by 60. The whole-number part becomes hours and the remainder becomes minutes. A minus sign applies to the entire result when subtractions exceed additions.
Example: combining two sessions
2h 45m + 1h 30m = 165 + 90 = 255 minutes = 4h 15m. In decimal hours, that is 4.25 hours.
Example: a negative balance
1h 15m − 2h 00m = 75 − 120 = −45 minutes. The result is −0h 45m, meaning a deficit of 45 minutes. It is not a clock time on the previous day.
When the total is more than one day
20h 45m + 8h 30m = 29h 15m. This is 1 day, 5 hours, and 15 minutes, but keeping it in hours can make project logs or session totals easier to compare.
Entering decimal time correctly
Do not enter 1.5 in the hours field. Enter 1 hour and 30 minutes instead. To convert a fractional hour to minutes, multiply the fraction by 60: 0.25 hours is 15 minutes and 0.75 hours is 45 minutes.
Common questions
Can I enter 90 minutes?
Use 1 hour and 30 minutes. The minutes field accepts whole numbers from 0 to 59 so each entry has a consistent format.
Can I mix addition and subtraction?
Yes. Choose Add or Less for each row. Entries are combined as signed durations; the first row can also be a subtraction.
Can this calculate an arrival time?
This tool adds durations rather than dates or clock readings. Use the hours calculator to find a duration between two clock times.