Time Duration Calculator
⏱️ Hours Worked Calculator
➕ Add / Subtract Durations
About this calculator
Two tools in one: a Hours Worked Calculator that takes a start time, an end time and a lunch break and returns net hours worked, and an Add or Subtract Duration tool for sums such as 2 hours 30 minutes plus 1 hour 45 minutes.
The hours-worked result also appears in decimal form, which is the format most payroll systems and invoices need. 8 hours and 30 minutes becomes 8.5.
How to use it
- Enter the Start Time and End Time.
- Enter the Lunch Break in minutes.
- Read the hours and minutes worked and the decimal hours.
- For sums, enter two durations and choose add or subtract.
Calculation
Worked = (End − Start) − Break. Decimal hours = Minutes worked ÷ 60. For durations, both are converted to minutes, added or subtracted, and converted back to hours and minutes.
Worked example
09:00 to 17:30 with a 30-minute lunch
| Time worked | 8 h 0 min |
| Decimal hours | 8.00 |
| 2 h 30 min + 1 h 45 min | 4 h 15 min |
For a weekly timesheet, add the decimal hours of each day and multiply by your hourly rate.
Tips and common mistakes
- Use decimal hours on invoices, since rates are per hour.
- Record the break honestly. Unpaid breaks must be removed for a correct total.
- If the shift runs past midnight, add 24 hours to the end time.
- Round to the nearest quarter hour if your employer does.
- For payroll across several days, add decimal hours.
Frequently asked questions
How do I calculate hours worked?
Subtract the start time from the end time and then subtract unpaid breaks.
How do I convert 7 h 45 min to decimal?
7 + 45 ÷ 60 = 7.75 hours.
Can I add durations?
Yes. Enter two durations and choose plus.
What if I work overnight?
Add 24 hours to the end time before calculating.
Does the tool deduct breaks?
Yes, enter the break length in minutes.
Why is decimal time needed?
Pay rates and invoices are per hour, so minutes must be converted to fractions of an hour.