How to Calculate Hours Worked
Whether you are filling out your time card, verifying your biweekly paycheck, or calculating hours for client billing, calculating hours worked requires three mathematical steps.
Work Hours = (Clock-Out Time − Clock-In Time) − Unpaid Break Minutes.
Example: Working 8:00 AM to 5:00 PM (9 elapsed hours) minus a 30-minute unpaid lunch equals 8 hours and 30 minutes of payable work, or 8.50 decimal hours for payroll (8 + 30/60).
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The 3 Steps to Calculate Hours Worked
1Determine Elapsed Shift Time
Subtract your start time from your end time. If using 12-hour clock notation, convert afternoon times to 24-hour military time by adding 12 to PM hours.
2Subtract Unpaid Meal Breaks
If you took an unpaid 30-minute lunch or 45-minute meal period, subtract those minutes from the elapsed shift time. Short paid breaks (5–20 minutes) should not be deducted.
3Convert Minutes to Decimal Hours for Payroll
Payroll systems multiply hourly wages by decimal hours rather than minutes. To convert minutes into decimals, divide the remaining minutes by 60:
Full Weekly Time Card Example
Here is an example timesheet for an employee working standard retail or office shifts:
| Day | Shift In / Out | Break | Hours & Min | Decimal |
|---|---|---|---|---|
| Monday | 8:00 AM – 4:30 PM | 30 min | 8h 00m | 8.00 |
| Tuesday | 8:00 AM – 5:00 PM | 30 min | 8h 30m | 8.50 |
| Wednesday | 8:15 AM – 5:00 PM | 45 min | 8h 00m | 8.00 |
| Thursday | 8:00 AM – 5:30 PM | 30 min | 9h 00m | 9.00 |
| Friday | 8:00 AM – 4:30 PM | 30 min | 8h 00m | 8.00 |
| Weekly Total: | 41h 30m | 41.50 hrs | ||
In this scenario, the worker completed 40.00 regular hours and 1.50 overtime hours.
Common Calculation Pitfalls to Avoid
Authoritative Sources & Regulatory Standards
- U.S. Department of Labor, Wage and Hour Division: 29 CFR Part 785 — Hours Worked (§ 785.18 Rest periods; § 785.19 Meal periods).
- Fair Labor Standards Act of 1938 (FLSA), as amended, 29 U.S.C. § 207 (Maximum Hours and Overtime Compensation).
Note: This guide provides standard mathematical procedures. State laws (such as California daily overtime rules) and collective bargaining agreements may specify additional requirements.