How to Calculate Work Hours and Overtime
6 min read · Updated September 26, 2026 · by Thomas M, Registered Investment Adviser (South Carolina)
Timesheets look simple until breaks, overnight shifts and overtime show up. This guide shows how to calculate hours worked by hand, how to convert minutes to decimals for payroll and how overtime pay works, with an example.
Hours between two times
Subtract the start time from the end time, then subtract any unpaid break. A shift from 09:00 to 17:30 is 8 h 30 min; with a 30-minute break it is 8 hours. Working in 24-hour time avoids am/pm mistakes: 17:30 is 5:30 p.m.
Overnight shifts
If the end time is earlier than the start, the shift crosses midnight: add 24 hours to the end time. 22:00 to 06:00 is 6:00 + 24:00 − 22:00 = 8 hours. The work hours calculator does this automatically — one 22:00–06:00 line gives 8:00 (8 hours).
Minutes to decimal hours
| Minutes | Decimal hours |
|---|---|
| 15 | 0.25 |
| 30 | 0.50 |
| 45 | 0.75 |
| 10 | 0.17 |
| 20 | 0.33 |
Divide the minutes by 60. So 7 h 45 min is 7.75 hours, not 7.45. This is the number payroll systems multiply by the hourly rate.
Overtime
Many employers pay overtime for hours above a weekly threshold (40 in the US under many rules) at a premium such as 1.5×. Five 10-hour days at $20 an hour: 40 regular hours ($800) plus 10 overtime hours at $30 ($300) = $1,100.00. Rules differ by country, state and contract — some pay daily overtime, weekend premiums or double time — so check your own.
Tips for accurate timesheets
- Record start and end times daily, not from memory at week’s end.
- Be clear whether breaks are paid or unpaid.
- Round consistently according to your employer’s policy.
- Keep a copy of your hours to check against your payslip.
Practice questions
Test yourself, then tap to check. Answers are calculated by the tools linked below.
- Mon–Fri 08:30 to 17:00 with a 45-minute break each day. How many hours, and what is the gross pay at $18/hour (no overtime)?
Show answer
Total hours worked: 38:45 (38.75 hours) · Gross pay: $697.50
- How many hours and minutes are there between 8:00 AM and 4:30 PM?
Show answer
Elapsed time: 8h 30m
- What is $32.50 an hour as an annual salary on a 40-hour week?
Show answer
Annual salary: $67,600.00 · Hourly rate: $32.50
Frequently asked questions
How do I calculate hours worked?
End time minus start time minus unpaid breaks, adding 24 hours if the shift crosses midnight.
How do I convert 7 hours 45 minutes to decimal?
7 + 45 ÷ 60 = 7.75 hours.
How is overtime calculated?
Hours above the weekly (or daily) threshold are paid at a multiplier, commonly 1.5 times the normal rate.
Do breaks count as work time?
It depends on whether they are paid; unpaid breaks are subtracted.
Try it yourself
Work Hours CalculatorAdd up hours worked from start and end times with breaks and overnight shifts, plus overtime and gross pay.
Time Duration CalculatorFind the hours and minutes between two times of day, including overnight shifts.
Salary Calculator (Hourly to Annual)Convert hourly, daily, weekly, bi-weekly, monthly or annual pay into every other period, with an optional take-home estimate.Keep learning
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