About the Time Calculator
The time calculator adds and subtracts amounts of time given in days, hours, minutes and seconds, and shows the total both in words (2 days, 1 hour, 40 minutes) and as a clock total (49:40:00). It turns 30 hours into 1 day and 6 hours for you.
Two more modes work with dates: find the time between two dates and times, for example the length of a night shift or a trip, and add or subtract time from a date and time to see when something will end or began.
All calculations run in your browser with clock times, so time zones and daylight-saving changes cannot shift the result.
How to use it
- Choose Add & subtract, Time between, or Date & time ± time.
- Add & subtract: enter days, hours, minutes and seconds in each row, choose + or − for the row, and add rows with Add row. Decimals such as 1.5 hours are fine.
- Time between: enter the start and end dates and times, or press Now. If the end is before the start the result is negative; use Swap to exchange them.
- Date & time ± time: enter a date and time, choose Add or Subtract and enter the amount. Use as start lets you chain several steps.
- Read the result and the totals in days, hours, minutes and seconds, and use Copy to copy the result.
Features
- Days, hours, minutes and seconds: Every mode counts days as well as hours, so long durations are shown as 3 days, 4 hours instead of only 76 hours.
- Add and subtract many times: Up to 20 rows, each added or subtracted, for timesheets, travel legs or video lengths.
- Time between two moments: Works across midnight, month ends and leap days, for example from 22:00 to 06:30 the next morning.
- Date and time after a duration: See the weekday, date and time after adding or subtracting time, written in your language.
- Totals in every unit: The same result as total days, hours, minutes and seconds, with decimals in your language’s style.
Examples
Weekly hours
Add five rows of 7 hours 45 minutes to get 1 day, 14 hours, 45 minutes, or 38:45:00 in clock form.
Night shift
From 29 October 22:00 to 30 October 06:30 is 8 hours, 30 minutes.
Deadline in 2 days 8 hours
From Wednesday 4 November 2026 09:00, adding 2 days, 8 hours and 30 minutes gives Friday 6 November at 17:30.
Limitations and notes
- Times are clock times: time zones and daylight-saving changes are not considered, so an hour that is skipped or repeated when the clocks change still counts as one hour.
- Adding time to a date and time rounds the result to whole seconds.
- Years from 1 to 9999 are supported, and a total can be at most about 11.57 million days.
- Months and years are not offered as units because their length varies; use the Date Difference Calculator for them.
Frequently asked questions
How do I add hours and minutes?
Choose Add & subtract, type the hours and minutes in the first row, the next amount in the second row, and add rows as needed. The total appears at once.
How do I calculate hours between two times that cross midnight?
Choose Time between and give the end time the next day’s date, for example 22:00 today to 06:30 tomorrow.
Can I enter decimals?
Yes. 1.5 hours is 1 hour and 30 minutes. Pages in German, French, Spanish and Portuguese use a decimal comma (1,5).
Why is my result negative?
The subtracted rows are larger than the added ones, or the end is before the start. In Time between, Swap exchanges the start and the end.
Is anything uploaded?
No. Everything is calculated in your browser.