Add and subtract hours, minutes and seconds, find the clock time after a duration, or measure how long it is between two dates and times.
Add or subtract time
Hours
Minutes
Seconds
Hours
Minutes
Seconds
Hours
Minutes
Seconds
Total (h:mm:ss)
0:00:00
Decimal hours
0
Total minutes
0
Days & hours
0d 0h 0m 0s
Add time to a clock time
Result
–
Time between two dates and times
Duration
–
Choose both dates to see the time between them.
Runs entirely in your browser. Nothing you enter is uploaded or stored on a server.
How to use the time calculator
To add or subtract durations, enter hours, minutes and (optionally) seconds in each row, choose + or − and add as many rows as you need.
To find what time it will be, enter a clock time in the second calculator and add or subtract hours and minutes.
To measure the time between two dates, pick a start and end date and time in the third calculator.
Results appear instantly in hours:minutes:seconds, decimal hours and total minutes.
How adding and subtracting time works
Time uses base 60: there are 60 seconds in a minute and 60 minutes in an hour. That is why a normal
calculator gets it wrong: 2.45 + 3.30 gives 5.75, but 2 h 45 min + 3 h 30 min is really 6 h 15 min.
This calculator converts everything to seconds, does the sum, and converts back.
Worked examples
Calculation
Result
Decimal hours
2:45 + 3:30
6:15
6.25
8:00 − 1:45
6:15
6.25
1:20:30 + 0:50:45
2:11:15
2.1875
9:00 AM + 8 h 30 min
5:30 PM
–
10:00 PM + 9 h
7:00 AM (next day)
–
Common uses
Totalling time spent on tasks or projects for invoices.
Adding up video, audio or lap times (hours, minutes, seconds).
Finding when a shift, flight or cooking timer will end.
Measuring elapsed time between two dates, such as hours until a deadline.
Add the hours and the minutes separately, then turn every 60 minutes into 1 hour. For example 2:45 + 3:30 = 5 hours 75 minutes = 6:15. Enter each value in its own row above and the calculator carries the minutes over for you.
How do I subtract time?
Change the sign of a row to “−”. For example 8:00 − 1:45 = 6:15. If the result is negative, it is shown with a minus sign.
What time will it be in X hours?
Use “Add time to a clock time”: enter the starting time, choose + or −, and enter the hours and minutes. The result shows the new clock time and whether it falls on the next or previous day.
Can I enter more than 60 minutes or 24 hours?
Yes. You can type 90 minutes or 30 hours and the total is normalised automatically. Totals over a day are also shown in days, hours, minutes and seconds.
How do I convert the total to decimal hours?
The decimal result is shown next to the hours:minutes total. You can also use the decimal hours converter for a full minutes-to-decimal chart.
Does the date-to-date duration handle daylight saving time?
Yes. The two dates and times are read in your device’s local time zone, so if a daylight-saving change happens between them, the hour gained or lost is included in the result.