How to Add and Subtract Time (Free Hours Calculator)
Time math is fiddly because it's base-60, not base-10 — 90 minutes isn't 1.9 hours, it's 1 hour 30 minutes. Whether you're totaling a timesheet, working out a cooking schedule, or figuring out how long a shift ran, a calculator that speaks hours-minutes-seconds saves the mental gymnastics. Here's how to add and subtract time for free.
Add or subtract a duration
Open the Time Calculator and use the Add / Subtract tab:
- Enter the first time as hours, minutes, and seconds.
- Choose + or −.
- Enter the second time — the result updates instantly (and can exceed 24 hours for timesheets).
Find the duration between two times
Switch to the Durationtab, enter a start and end time, and you'll get the gap between them. If the end is earlier than the start, it's treated as the next day — handy for overnight shifts.
Common uses
- Timesheets — add up hours worked across a week.
- Cooking — work out when to start so everything's ready together.
- Scheduling — how long between two events, or when something ends.
Working with dates instead?
If you need days rather than hours, the Date Difference calculator counts days between two dates, and the Age Calculator gives an exact age. Browse all the calculators in one place.
FAQ
Can it total more than 24 hours?
Yes — results can exceed 24 hours, which is what you want for weekly timesheets.
Does it handle overnight (across midnight)?
Yes — in Duration mode, an end time earlier than the start is treated as the next day.
Is it free?
Yes, free and instant, with no sign-up.