Time calculator

A time calculator adds and subtracts hours, minutes and seconds. Total several durations (2:45 + 1:30 = 4:15), find the clock time or date a duration before or after a given moment, or measure the time between two times, including spans that cross midnight. Results update as you type.

Add or subtract Clock or date ± time Time between

Add or subtract durations

Row 1: add or subtract
Row 1 hours
Row 1 minutes
Row 1 seconds
Row 2: add or subtract
Row 2 hours
Row 2 minutes
Row 2 seconds

Total time

4:16:20

4 hours 16 minutes 20 seconds

Decimal hours: 4.27
Total minutes: 256.33
Total seconds: 15,380

Paste a list of times

One time per line

Use h:mm:ss (2:45:30), h:mm (1:30 is 1 hour 30 minutes), or a number with a unit: 1.5h, 45m, 90s or 1h 30m. Start a line with - to subtract it. Up to 500 lines.

Read two-part times as minutes:seconds (45:30 = 45 min 30 s)

Spreadsheet formula

For Excel or Google Sheets. Format the cell as [h]:mm:ss:

=(2*3600+45*60+30+1*3600+30*60+50)/86400

Or in decimal hours (format the cell as a number):

=(2*3600+45*60+30+1*3600+30*60+50)/3600

Minutes and seconds can be over 59; they carry over. Up to 500 rows.

How it's worked out

Each amount is turned into seconds, the seconds are added or subtracted, and the total is split back into hours, minutes and seconds. Working in whole seconds means there are no rounding errors, however many rows you add. Minutes and seconds can be any size: 90 minutes is carried over as 1 hour 30 minutes.

Adding: 2:45:30 + 1:30:50

Seconds: 30 + 50 = 80 seconds, which is 1 minute 20 seconds. Write 20, carry 1 minute.
Minutes: 45 + 30 + 1 carried = 76 minutes, which is 1 hour 16 minutes. Write 16, carry 1 hour.
Hours: 2 + 1 + 1 carried = 4 hours. The total is 4:16:20, or 4.27 decimal hours.

Subtracting: 1:20:00 − 2:25:00

The second time is bigger, so the answer is negative. Take the smaller from the larger: 2:25:00 − 1:20:00 = 1:05:00, then add the minus sign: −1:05:00. When you need to borrow, turn one hour into 60 minutes: 5:10 − 2:45 becomes 4:70 − 2:45 = 2:25.

Clock time: 9:30 PM + 3 hours 45 minutes

On a 24-hour clock 9:30 PM is 21:30. Adding 3:45 gives 25:15. Anything past 24:00 rolls into the next day, so take away 24 hours: 1:15 AM the next day. Subtracting past midnight works the same way in reverse and lands on the previous day.

Date and time: Monday, October 5, 2026 at 9:30 PM + 1 day 2 hours

Add the whole days to the date first (Tuesday, October 6), then the hours to the clock: 9:30 PM plus 2 hours is 11:30 PM. The result is Tuesday, October 6, 2026 at 11:30 PM, or 2026-10-06T23:30 in ISO format.

Clock and date results assume normal 24-hour days. On the night the clocks change for daylight saving time, the real elapsed time is an hour more or less.

Adding times in Excel or Google Sheets

Type durations as h:mm:ss (for example 2:45:30), one per cell, then use:

Total of A2 to A6, formatted as [h]:mm:ss so it can pass 24 hours:

=SUM(A2:A6)

The same total in decimal hours (format the cell as a number):

=SUM(A2:A6)*24

A clock time in A2 plus 3 hours 45 minutes:

=A2+TIME(3,45,0)

Spreadsheets store times as fractions of a day, which is why multiplying by 24 gives hours. The square brackets in [h] stop the hours from wrapping back to 0 after 24. TIME() only takes up to 23 hours, 59 minutes and 59 seconds per argument, so the formula under the calculator is written in seconds and divided by 86,400 instead.

Which calculator do you need?

Time calculator: add and subtract hours, minutes and seconds, or a duration to a date and time.
Time duration calculator: the time between two times or two dates and times.
Hours calculator: hours worked, shifts, breaks and weekly or biweekly timesheets.
Date duration: days, weeks and months between two dates.

Related tools

Frequently asked questions

How do I add hours and minutes together?

Add the minutes and the hours separately, then carry every 60 minutes over as an hour. For example, 2:45 + 1:30 is 3 hours 75 minutes, and 75 minutes is 1 hour 15 minutes, so the total is 4:15. Subtracting works the same way in reverse: borrow an hour as 60 minutes when you need to, so 5:10 − 2:45 is 2:25.

How do I add up a list of times?

Open "Paste a list of times" under the calculator, paste one time per line (such as 2:45:30, 1:30, 1.5h or 45m) and choose Add to rows. Lines that start with a minus sign are subtracted, and any line that cannot be read is listed with its line number.

What happens when adding time goes past midnight?

The clock starts again at 12:00 AM and the result is on the next day. For example, 9:30 PM plus 3 hours 45 minutes is 1:15 AM the next day. Subtracting past midnight gives a time on the previous day.

Can I add hours to a date and time?

Yes. In the "Clock or date ± time" tab, fill in the optional date and add days, hours, minutes and seconds. The result is shown as a full date and time, such as Tuesday, October 6, 2026 at 11:30 PM, and in ISO format.

How do I convert hours and minutes to decimal hours?

Divide the minutes by 60 and add them to the hours. 2 hours 15 minutes is 2 + 15 ÷ 60 = 2.25 hours, and 4 hours 20 minutes is about 4.33 hours. To go back, multiply the decimal part by 60.

How do I add up times in Excel or Google Sheets?

Enter each duration as h:mm:ss, add them with =SUM(A2:A6), and format the total as [h]:mm:ss so it keeps counting past 24 hours. Multiply by 24, as in =SUM(A2:A6)*24, to get decimal hours. The calculator also writes a ready-made formula for your rows. Excel shows ##### for a negative time in its default date system, so use decimal hours for negative totals.