Time Calculator
Add and subtract durations in days, hours, minutes and seconds, find the time between two times, or add hours and minutes to a clock time.
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How to use Time Calculator
- 1
Open Time Calculator on this page. It loads right in your browser.
- 2
Add your file, text or values and adjust the settings.
- 3
Copy the result or download it. Nothing is uploaded or stored.
How to use it: Time Calculator
This time calculator does the awkward base-60 arithmetic for you. Add or subtract any number of durations (days, hours, minutes and seconds) and see the total in a readable form, in decimal hours, minutes, seconds and hh:mm:ss.
Two more modes cover everyday questions: Time between two times (handles overnight spans like 22:00 to 06:30) and Add time to a clock time, which tells you what time it will be after 3 h 45 min and whether it rolls into the next day.
How to use it
- Choose Add & subtract time, Time between two times, or Add time to a clock time.
- Enter durations row by row; tap + / − on a row to subtract it.
- Or enter a start and end time, or a start time plus hours and minutes.
- Read the result in several formats.
How it is calculated
All values are converted to seconds (1 day = 86,400 s, 1 hour = 3,600 s, 1 minute = 60 s), added or subtracted, then split back into days, hours, minutes and seconds. Decimal hours = seconds ÷ 3,600.
Worked example
2 h 45 min + 1 h 30 min 20 s = 4 h 15 min 20 s, or 4.2556 decimal hours. From 09:15 to 17:40 is 8 h 25 min (8.42 hours). Adding 3 h 45 min to 22:30 gives 02:15 the next day.
Who uses it
- Adding up video, audio or workout durations
- Working out shift lengths and time differences
- Planning travel and cooking times
- Converting time to decimal hours for invoices
Tips
- For a weekly timesheet with breaks and overtime, use the hours calculator.
- Decimal hours are what most payroll and invoicing tools expect: 1 h 30 min is 1.5, not 1.30.
- An end time earlier than the start is treated as the next day.
Free, private and instant: every calculation runs in your browser, nothing is uploaded or stored, and there is no sign-up or limit. Related calculators: hours calculator, date calculator, age calculator.
Features
- Add and subtract days, hours, minutes and seconds
- Time between two clock times, overnight included
- Add or subtract time from a clock time
- Decimal hours and hh:mm:ss output
- Unlimited rows
Frequently asked questions
How do I add hours and minutes?
Enter each duration as a row and the calculator totals them, carrying 60 minutes into an hour automatically.
How do I calculate the time between two times?
Use Time between two times and enter the start and end. 08:45 to 17:15 is 8 h 30 min.
How do I convert minutes to decimal hours?
Divide by 60: 45 minutes is 0.75 hours, so 7 h 45 min is 7.75 hours.
What time will it be in 8 hours?
Use Add time to a clock time, enter the current time and 8 hours; the result shows the time and if it is the next day.
Can I subtract durations?
Yes. Tap the + button on a row to turn it into −, and that row is subtracted from the total.
Is this calculator free and private?
Yes. It is completely free, needs no account and runs entirely in your browser, so the numbers you type are never sent to a server or stored.