Adding up times is awkward because there are 60 minutes in an hour and 60 seconds in a minute, so the normal base-10 rules don’t apply. The Time Calculator handles it for you, with three modes:
- Add time: add two durations, such as 2 h 45 m + 1 h 30 m.
- Subtract time: find the difference between two durations.
- Duration: find how long it is between a start time and an end time, including overnight shifts that cross midnight.
Results are shown as hh:mm:ss, as hours and minutes, and as total minutes and seconds. That is useful for timesheets, overtime, billing, video editing, cooking and workout logs.
How to use the time calculator
- Choose a tab: Add time, Subtract time or Duration.
- For add or subtract, enter hours, minutes and seconds for both durations. Values above 59 are fine: 90 minutes is converted automatically.
- For duration, pick the start and end clock times.
- Press Calculate.
How time arithmetic works
The calculator converts everything to seconds, does the sum, then converts back:
hours = floor(total ÷ 3600) · minutes = floor((total mod 3600) ÷ 60) · seconds = total mod 60
Adding: 2 h 45 m 50 s + 1 h 30 m 25 s
Seconds: 50 + 25 = 75 = 1 m 15 s. Minutes: 45 + 30 + 1 = 76 = 1 h 16 m. Hours: 2 + 1 + 1 = 4. Result: 4:16:15.
Overnight shift duration: 22:00 to 06:30
The end time is earlier than the start, so the shift crosses midnight. The calculator adds 24 hours: (6:30 + 24:00) − 22:00 = 8 hours 30 minutes.
Decimal hours vs hours and minutes
Payroll and billing systems often want decimal hours, where 7 h 45 m is entered as 7.75, not 7.45. Convert minutes by dividing by 60:
| Minutes | Decimal hours | Minutes | Decimal hours |
|---|---|---|---|
| 6 min | 0.10 | 30 min | 0.50 |
| 12 min | 0.20 | 36 min | 0.60 |
| 15 min | 0.25 | 45 min | 0.75 |
| 20 min | 0.333 | 48 min | 0.80 |
| 24 min | 0.40 | 50 min | 0.833 |
To go back from decimal: 0.85 h × 60 = 51 minutes, so 8.85 h = 8 h 51 m.
Weekly timesheet example
| Day | In | Out | Break | Worked |
|---|---|---|---|---|
| Mon | 09:15 | 18:30 | 45 m | 8 h 30 m |
| Tue | 09:00 | 18:00 | 1 h | 8 h 00 m |
| Wed | 09:30 | 19:15 | 45 m | 9 h 00 m |
| Thu | 09:05 | 17:50 | 40 m | 8 h 05 m |
| Fri | 09:00 | 16:30 | 30 m | 7 h 00 m |
| Total | 40 h 35 m = 40.58 h | |||
Use Duration for each day, subtract the break with Subtract time, then Add time the daily totals.
Working-hour rules in India
Under the Factories Act and most state Shops & Establishments Acts, adult workers generally may not work more than 9 hours a day or 48 hours a week. Overtime is paid at twice the ordinary rate, and a rest break is required after about 5 hours. The new Labour Codes keep the 48-hour weekly limit and let states set flexible daily patterns. Check your state’s rules and your employment contract.
Other handy conversions
- 1 day = 24 h = 1,440 min = 86,400 s
- 1 week = 168 h = 10,080 min
- 1,000 minutes = 16 h 40 m
- A 2 h 28 m film = 148 minutes
Frequently asked questions
How do I add hours and minutes together?
Add the minutes. If the total is 60 or more, carry 1 hour for every 60 minutes, then add the hours. 3 h 50 m + 2 h 25 m = 5 h 75 m = 6 h 15 m.
How do I calculate hours worked across midnight?
Use the Duration tab with your start and end times. If the end is earlier than the start, the calculator adds 24 hours. 21:00 to 05:00 is 8 hours.
How do I convert minutes to decimal hours?
Divide the minutes by 60. 45 minutes = 0.75 hours, so 7 h 45 m = 7.75 h.
What does a negative result mean in subtract mode?
The second duration is longer than the first. The calculator shows the difference with a minus sign.
Can I enter more than 60 minutes?
Yes. Enter 135 minutes and the calculator treats it as 2 hours 15 minutes.