How to add hours and minutes
Add the hours and the minutes separately. Every 60 minutes makes one more hour, so divide the minutes by 60, carry the whole hours over, and keep the remainder as minutes.
Adding a week of shifts from a time card:
- Monday
- 8:15
- Tuesday
- 7:50
- Wednesday
- 8:40
- Thursday
- 9:05
- Friday
- 6:30
- Hours and minutes
- 38 h + 140 min
- Carry
- 140 min = 2 h 20 min
- Total
- 40:20 (40.33 hours)
That week is 20 minutes over 40 hours. If you have start and end times for each day instead of lengths, the time card calculator adds up the week and works out the overtime.
How to subtract time
Subtract minutes from minutes and hours from hours. If the top minutes are smaller, borrow one hour and add 60 to the minutes.
For example, take a 45-minute lunch off a 9:10 day. Ten minutes is less than 45, so rewrite 9:10 as 8:70. Then 8:70 − 0:45 = 8:25.
Subtracting also shows how much is left. If you have worked 32:45 so far this week, 40:00 − 32:45 = 7:15 before you reach overtime. In the calculator, any line can be subtracted from the total, such as a break or a correction.
Converting the total to decimal hours
Payroll often uses decimal hours. Divide the minutes by 60 and add the result to the hours: 40:20 is 40 + 20 ÷ 60 = 40.33 hours. Watch the format, because 8:30 is eight and a half hours, or 8.50, not 8.30.
| Hours and minutes | Decimal hours |
|---|---|
| 0:05 | 0.08 |
| 0:10 | 0.17 |
| 0:15 | 0.25 |
| 0:20 | 0.33 |
| 0:30 | 0.50 |
| 0:40 | 0.67 |
| 0:45 | 0.75 |
| 0:50 | 0.83 |
Convert the total, not each line. Three periods of 0:20 add up to exactly 1:00, or 1.00 hour, but rounding each one to 0.33 first gives 0.99. The decimal hours chart lists every minute from 1 to 60.
Clock times and durations
A clock time is a moment in the day, like 5:30 PM. A duration is an amount of time, like 5 hours and 30 minutes. This calculator adds durations, so a total can go past 24:00: a week of work might be 42:15.
To get a duration from two clock times, subtract the start from the end: 9:00 AM to 5:30 PM is 8:30. The hours calculator does this for one shift, including shifts past midnight, and the time card calculator with lunch does it for a week of lunch punches. Adding a duration to a clock time gives a new clock time: 9:00 AM plus 8:30 is 5:30 PM. For 24-hour times like 1730, see the military time converter.
Questions
How do I add hours and minutes together?
Add the hours, then add the minutes. For every 60 minutes, add 1 hour and subtract 60 from the minutes. 3:45 + 2:30 is 5 hours and 75 minutes, which is 6:15.
How do I convert hours and minutes to decimal?
Divide the minutes by 60 and add them to the hours. 1 hour 45 minutes is 1 + 45 ÷ 60 = 1.75 hours.
Why is my total more than 24 hours?
The total is an amount of time, not a time of day, so it keeps counting past 24. Two 13-hour shifts add up to 26:00.
How many hours do I have left until 40?
Subtract the hours you have worked from 40:00. After 35:20, you have 4:40 left, or 4.67 hours.
Can I add times written in decimal hours?
Yes, as long as every number is in decimals: 7.5 + 8.25 = 15.75 hours, which is 15:45. Do not mix formats, because 7.30 in decimals is 7 hours 18 minutes, not 7:30.
How do I subtract two clock times?
Subtract the start from the end. If the minutes are smaller, borrow an hour. From 8:50 AM to 4:20 PM is 16:20 − 8:50, which becomes 15:80 − 8:50 = 7:30. The hours calculator does this for you.