Calculate Hours Worked

Formula: Hours worked = clock-out − clock-in − excluded breaks

For an overnight shift, treat clock-out as occurring on the following day.

How to calculate hours worked

Find the elapsed time between the start and end of a shift, then subtract any break that should not count as worked time.

Example: 8:15 AM to 5:00 PM is 8 hours 45 minutes. Subtract a 30-minute excluded lunch and the result is 8 hours 15 minutes, or8.25 decimal hours.

A reliable manual process:

1. Check AM/PM carefully.
2. Subtract start time from end time.
3. If the shift crosses midnight, continue the end time into the next day.
4. Subtract only breaks that should be excluded.
5. Add exact daily durations for a weekly total.
6. Convert minutes to decimals only when needed.

Do not treat minutes as hundredths. 8 hours 30 minutes is 8.5 hours, not 8.30 hours.

Work-hours examples

Calculating hours with lunch or other breaks

Calculate the full elapsed shift, then subtract a break only if it should be excluded from the worked-time total you need.

8:00 AM → 5:00 PM = 9 hours

With a 45-minute excluded lunch: 9:00 − 0:45 = 8 hours 15 minutes

For payroll or compliance, whether a break is compensable can depend on applicable law, policy, agreements, and what occurred during the break. The calculator totals your inputs; it does not determine a break's legal status.

How to calculate an overnight shift

A shift from 10:30 PM to 6:30 AM lasts 8 hours: 1 hour 30 minutes before midnight plus 6 hours 30 minutes after midnight.

An end time earlier on the clock can therefore mean "next day," not a negative duration. For shifts longer than 24 hours or ambiguous dates, record dates as well as times.

For U.S. employers using work-time records for payroll, the Department of Labor requires covered employers to keep accurate records of hours worked. See theU.S. Department of Labor's FLSA recordkeeping guidance.

Hours and minutes vs decimal hours

Convert minutes with minutes ÷ 60. Use the hours to decimal converter for this step, or thedecimal hours calculator if you need to convert in both directions. Converting a standalone number of minutes rather than a full shift? Use theminutes to decimal calculator.

Avoid unnecessary rounding

Add precise elapsed time first and round only at the stage required by the payroll or billing rule you follow. Rounding every shift can produce a different total from adding precise durations and rounding once.

A trustworthy calculator should preserve precise values internally and should not silently move punches to convenient intervals.

Overtime is a separate question

A weekly total tells you how long someone worked. It does not, by itself, establish which hours legally qualify for overtime. Rules vary by jurisdiction and worker circumstances.

If you already know the qualifying overtime hours, use the overtime calculator for the pay arithmetic.

Common mistakes

• 8:30 ≠ 8.30 decimal hours. It equals 8.50.
• Do not deduct lunch twice. Separate lunch clock-out/in punches may already remove it.
• Handle midnight explicitly. 11:00 PM to 7:00 AM is normally 8 hours.
• Do not round too early. Small errors can accumulate across shifts.