Time calculator

Add or subtract hours, minutes and seconds, or multiply and divide a length of time. The answer carries minutes into hours for you and shows decimal hours too.

Add or subtract two times
Multiply or divide a time by a number
Answer in h:mm:ss, decimal hours and minutes

Last updated October 28, 2026

How to use the time calculator

Enter the first time in hours, minutes and seconds. Leave any box you do not need at 0.
Pick an operation: add or subtract a second time, or multiply or divide by a number.
Enter the second time, or the number. The result updates as you type.
Read the answer as hours:minutes:seconds, or use the decimal hours for a timesheet or invoice.

How adding time works

Time counts in sixties, not tens: 60 seconds make a minute and 60 minutes make an hour. The calculator turns both times into seconds, does the sum, then turns the seconds back into hours, minutes and seconds.

total seconds = hours × 3,600 + minutes × 60 + seconds

To go back, divide the total by 3,600 for whole hours, divide what is left by 60 for minutes, and the remainder is seconds. Decimal hours are the total seconds divided by 3,600.

Worked example

Add 1 hour 45 minutes and 2 hours 30 minutes.

Add the hours: 1 + 2 = 3 hours.
Add the minutes: 45 + 30 = 75 minutes.
75 minutes is 1 hour 15 minutes, so carry the hour: 3 + 1 = 4 hours 15 minutes.

The answer is 4:15:00, or 4.25 decimal hours. Adding the times as decimals of the clock, 1.45 + 2.30, gives 3.75, which is wrong.

Minutes to decimal hours

Timesheets and payroll usually want decimal hours. Divide the minutes by 60.

Minutes	Decimal	Minutes	Decimal
5	0.08	35	0.58
10	0.17	40	0.67
15	0.25	45	0.75
20	0.33	50	0.83
25	0.42	55	0.92
30	0.50	60	1.00

Common questions

How do you add hours and minutes together?

Add the hours and the minutes separately. If the minutes come to 60 or more, take 60 away and add 1 to the hours. 1:45 plus 2:30 is 3 hours 75 minutes, which is 4 hours 15 minutes.

How do you subtract time?

Subtract the minutes first. If the top number is smaller, borrow an hour: take 1 from the hours and add 60 to the minutes. 5:10 minus 2:45 becomes 4:70 minus 2:45, which is 2 hours 25 minutes.

How do I convert hours and minutes to decimal hours?

Divide the minutes by 60 and add the result to the hours. 7 hours 20 minutes is 7 + 20 ÷ 60 = 7.33 hours.

How do you divide time?

Turn the time into minutes or seconds, divide, then turn it back. 5 hours divided by 3 is 300 minutes ÷ 3 = 100 minutes, or 1 hour 40 minutes.

Can I add more than two times?

Yes. Add the first two, then put the result in the first box and add the next one. For a whole week of shifts, the time card calculator adds each day for you.