Time Calculator: Add and Subtract Hours and Minutes
Add or subtract hours, minutes and seconds, or total a list of durations such as 1:45 + 2:30. Shows the result as h:mm:ss, in decimal hours and in total minutes and seconds.
- Result (h:mm:ss)
- 4:15:00
- Decimal hours
- 4.25
- Total minutes
- 255
- Total seconds
- 15,300
Pick a start time to see the time of day after the result.
About the Time Calculator
The Time Calculator adds and subtracts hours, minutes and seconds the way a clock does, so you never have to borrow 60 minutes in your head again. Use it to total the time spent on a project, to work out how long is left on a task, to add up the lengths of songs or video clips, or to find what time it will be after a long journey. It works in two ways: add or subtract two times given as days, hours, minutes and seconds, or add up a whole list of durations typed one per line.
Every value is stored as a whole number of seconds, so the result is exact. Hours are never wrapped at 24, which means 27 hours shows as 27:05:00 rather than jumping back to 3:05. Longer results are also written in days, for example 1 day 3:05:00.
How to use it
Add or subtract two times
- Fill in Time A with any of days, hours, minutes and seconds. Blank fields count as zero, and 90 minutes is accepted as it is.
- Choose Add or Subtract.
- Fill in Time B. The result appears at once as h:mm:ss, decimal hours, total minutes and total seconds. A result below zero shows a minus sign.
- Optionally pick a start clock time to see the time of day after the result, and whether it falls on the same day, the next day or earlier.
Add a list of times
Type one duration per line in any of these forms: 1:45, 1:45:30, 2h 30m, 90m, 45s, 1.5h or 1d 2h. Start a line with a minus sign to subtract it. Blank lines are skipped, and any line that cannot be read is named by its line number and left out of the total.
The formula
Each time is turned into seconds, added or subtracted, and turned back:
The hours in the result are , the minutes are and the seconds are .
Worked examples
- Adding with a carry: 1 h 45 min + 2 h 30 min. The minutes make 75, which is 1 hour and 15 minutes, so the total is 4:15:00, or 4.25 hours.
- Subtracting with borrowing: 3 h 10 min − 1 h 25 min. You cannot take 25 minutes from 10, so borrow one hour: 2 h 70 min − 1 h 25 min = 1:45:00.
- Going below zero: 30 min − 1 h gives −0:30:00, half an hour short.
- A list of tasks: 1:45, 2:30 and −0:15 add up to 4:00:00 from three entries.
- Past midnight: starting at 22:30 and adding 3 h 45 min reaches 02:15 (2:15 AM) the next day.
Decimal hours
Timesheets and invoices often need hours as a decimal. Divide the minutes by 60: 15 minutes is 0.25 hours, 30 minutes is 0.5 hours and 45 minutes is 0.75 hours. The calculator shows decimal hours to two places, so 1 h 20 min appears as 1.33.
Privacy
Nothing is uploaded; every calculation runs in your browser and never leaves your device.
Related tools
To find the hours worked between a start and an end time, with breaks, use the Hours Calculator. To change a value from one unit to another, such as minutes to hours, try the Time Converter. Count down or time a lap with the Online Timer, and add days or weeks to a calendar date with the Date Calculator.
Frequently asked questions
How do I add hours and minutes together?
Add the minutes first. If they come to 60 or more, carry one hour for every 60 minutes. For example 1 h 45 min + 2 h 30 min gives 75 minutes, which is 1 h 15 min, so the total is 4 h 15 min. The calculator does the carrying for you.
How do I subtract times when the minutes are smaller?
Borrow one hour and add 60 to the minutes. For 3 h 10 min − 1 h 25 min, rewrite the first time as 2 h 70 min, then subtract to get 1 h 45 min. If the second time is larger, the result is shown with a minus sign.
Which formats can I type in the list?
One duration per line as 1:45 (hours and minutes), 1:45:30 (with seconds), or with units such as 2h 30m, 90m, 45s, 1.5h and 1d 2h. A line that starts with a minus sign is subtracted. Blank lines are skipped and unreadable lines are listed by number.
Why does the result show more than 24 hours?
A duration is not a time of day, so the hours keep counting past 24. A total of 27 hours 5 minutes shows as 27:05:00 and also as 1 day 3:05:00. To get a time of day instead, enter a start clock time in the add mode.
How do I convert minutes to decimal hours?
Divide the minutes by 60. 15 minutes is 0.25 hours, 30 minutes is 0.50 and 45 minutes is 0.75. The calculator shows every result in decimal hours to two places, which is the form most timesheets and invoices use.
What time will it be after a given duration?
Pick a start clock time in the add mode. The calculator adds the result to it and shows the new time in 24-hour and 12-hour form, and says whether it is the same day, the next day or a number of days later or earlier. For example 22:30 plus 3 h 45 min is 02:15 the next day.