Time calculator

What is the Time Calculator?

The Time Calculator adds or subtracts two durations made up of hours, minutes, and seconds. It's built for anyone who needs to work out a total time without doing the hour/minute carrying math by hand — the kind of calculation that's easy to get wrong when you're converting between base-60 (minutes, seconds) and base-24 (hours) by hand.

Everything runs instantly in your browser, with no sign-up required and no data ever leaving your device.

How to use it

1. Enter the first time value in hours, minutes, and seconds.
2. Choose whether you want to add or subtract.
3. Enter the second time value.
4. The result updates instantly and is broken down cleanly into hours, minutes, and seconds.

How the math works

Behind the scenes, the calculator converts both time values entirely into seconds, performs the addition or subtraction on those totals, and then converts the result back into hours, minutes, and seconds — "carrying over" correctly whenever seconds exceed 60 or minutes exceed 60, exactly the way you would by hand but without the risk of a manual arithmetic slip.

Worked examples

Adding two durations

2 hours 45 minutes plus 1 hour 30 minutes: adding the minutes gives 75 minutes, which carries over as 1 hour 15 minutes, so the total is 3 hours + 1 hour 15 minutes = 4 hours 15 minutes.

Subtracting two durations

5 hours 10 minutes minus 2 hours 40 minutes: since 10 minutes is less than 40 minutes, the calculator borrows an hour, making it 4 hours 70 minutes, then subtracts to get 2 hours 30 minutes.

Common uses

• Adding up work shifts or timesheets across a week
• Calculating total cooking or baking time across multiple recipe steps
• Working out video or audio edit durations when combining clips
• Finding the time remaining between two clock durations, like a race split or workout segment
• Estimating total travel time across multiple legs of a journey
• Payroll and freelance billing calculations involving partial hours

A note on subtraction

If subtracting the second value from the first produces a negative result — meaning the second duration was actually larger than the first — the calculator shows a minus sign in front of the hours so you immediately know the result represents a negative (deficit) duration rather than a positive one.

Frequently asked questions

Can I enter more than 59 minutes or seconds?

Yes — if you type a value like 90 minutes, the calculator will correctly carry that over into hours as part of the calculation, so you don't have to pre-convert it yourself.

Is this the same as calculating the difference between two clock times (like 3:15 PM and 5:40 PM)?

Not quite — this tool works with durations (lengths of time), not fixed clock times. For finding the number of days or the gap between two dates and times, use the Date Calculator alongside this tool.