DailyCalc

Time Calculator: Add & Subtract Time

Add or subtract hours, minutes and seconds, or from a clock time.

What do you want to calculate?
First duration
Second duration

Leave any box blank for 0. Decimals work too, such as 1.5 hours.

Result

4 hours 15 minutes

2 hours 45 minutes plus 1 hour 30 minutes is 4 hours 15 minutes.

h:mm:ss
4:15:00
Total hours
4.25 hours
Total minutes
255 minutes
Total seconds
15,300 seconds
Total days
0.1770833333 days

Fix the highlighted field to update the result.

How to use

  1. Choose Add or subtract durations or Clock time ± duration.
  2. Fill in days, hours, minutes and seconds. Blank boxes count as 0, and decimals work.
  3. Pick Add or Subtract.
  4. In clock mode, add a start date to see the exact day of the result.

How time is calculated

  1. Each duration becomes seconds: days × 86,400 + hours × 3,600 + minutes × 60 + seconds.
  2. The totals are added or subtracted.
  3. The answer is split back into days, hours, minutes and seconds.

For a clock time, passing midnight moves the result to the next day. Going back past midnight moves it to the day before.

Examples

  • 2 h 45 min + 1 h 30 min = 3 h 75 min = 4 hours 15 minutes (4.25 hours).
  • 9:00 AM + 8 h 30 min = 5:30 PM the same day.
  • 10:30 PM + 3 h 45 min = 2:15 AM the next day.
  • 1:00 AM − 2 hours = 11:00 PM the day before.

Time units

Unit Seconds Minutes Hours
1 minute 60 1 0.0167
1 hour 3,600 60 1
1 day 86,400 1,440 24
1 week 604,800 10,080 168
Negative results and daylight saving

Subtracting a longer duration gives a negative answer, such as 1 h 15 min − 2 h 30 min = −1 h 15 min.

Clock results ignore daylight saving changes. On the night the clocks change, the real elapsed time differs by an hour.

Want the time between two clock times instead? Use the hours calculator.

Frequently asked questions

How do I add hours and minutes?

Add the minutes and the hours separately, then turn every 60 minutes into an hour. 2 h 45 min + 1 h 30 min = 3 h 75 min = 4 h 15 min.

What time will it be in 8 hours and 30 minutes?

Add the duration to the time now. From 9:00 AM it will be 5:30 PM. Choose the clock mode, tap Now and enter the duration.

How do I subtract time across midnight?

Subtract, and if the result is below zero, add 24 hours and move back a day. 1:00 AM minus 2 hours is 11:00 PM the day before.

How do I convert a duration to decimal hours?

Divide the minutes by 60 and add them to the hours. 4 hours 15 minutes is 4.25 hours.

Why is my result negative?

You subtracted a longer duration from a shorter one. 1 h 15 min minus 2 h 30 min is −1 h 15 min.

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