Time Calculator – Add and Subtract Hours & Minutes
Add or subtract hours, minutes and seconds.
About the Time Calculator
What is the Time Calculator?
A time calculator adds or subtracts two durations expressed in hours, minutes and seconds.
Why use this calculator?
Timesheets, video editing, workouts and cooking all involve combining or subtracting time spans, which is fiddly because the units are base-60.
How to use it
- Enter the first duration (hours, minutes, seconds).
- Choose add or subtract.
- Enter the second duration and read the result.
Formula
Convert both durations to seconds, combine them, then convert back to hours, minutes and seconds.
Negative results are shown with a minus sign and represent a duration the other way round.
Frequently Asked Questions
Can the result be negative?
Yes. If you subtract a larger duration from a smaller one, the result is negative and shown with a minus sign.
How do I add working hours?
Enter the hours and minutes for each period and use the add operation. Use the time card calculator for whole weeks.
Does it account for leap years?
Yes. The date logic follows the Gregorian calendar, including leap years and differing month lengths.
Are weekends and holidays excluded?
Only if the calculator says so. By default, results count every calendar day; use a business-day option where available.
Which time zone is used?
Calculations use whole calendar dates and are time-zone independent unless a time-of-day is involved.
Is this calculator free to use?
Yes. Every calculator on this site is completely free, with no hidden fees, no subscriptions and no limits on how many times you can use it.
How accurate are the results?
We use standard, widely accepted formulas and calculate in your browser using double-precision arithmetic. Results are rounded for readability, so treat them as reliable estimates rather than a guarantee. Real-world factors can vary the true figure.
Can I add this calculator to my own website?
Yes. Open this calculator page and use the "Add to your website" box in the sidebar to copy a ready-made iframe snippet, then paste it into any HTML page.
Does it work on a phone or tablet?
Yes. The layout is fully responsive, so it works on desktops, laptops, tablets and mobile phones, and every input adapts to touch screens.
Is the information I type kept private?
Yes. All calculations run locally in your browser. Nothing you enter is uploaded, stored or shared with anyone.