How to Calculate Hours Worked
To calculate hours worked: end time − start time − unpaid breaks, then convert the minutes to decimal hours for payroll. A shift from 8:30 AM to 5:15 PM with a 45-minute lunch is 8 hours exactly.
Step by step
- Write each time in 24-hour format so the afternoon is easy to subtract: 5:15 PM = 17:15.
- Subtract the start from the end. If the minutes of the end time are smaller, borrow an hour: 17:15 − 8:30 = 16:75 − 8:30 = 8:45.
- Take off unpaid breaks: 8:45 − 0:45 = 8:00.
- Convert minutes to decimal hours (minutes ÷ 60): 8:00 = 8.00; 7:45 would be 7.75.
- Add up the days of the workweek and apply overtime over 40 hours.
For a night shift that crosses midnight, add 24 hours to the end time: 10:00 PM to 6:30 AM is 30:30 − 22:00 = 8:30.
- Time at work
- 8:45 (8:30 AM – 5:15 PM)
- Break
- 45 min
Converting minutes to decimal hours
Payroll systems multiply hours by a rate, so they need decimal hours. 30 minutes is 0.5, 15 minutes is 0.25, 45 minutes is 0.75, and every minute is 1/60 ≈ 0.0167 hours.
| Minutes | Decimal | Minutes | Decimal |
|---|---|---|---|
| 5 | 0.08 | 35 | 0.58 |
| 10 | 0.17 | 40 | 0.67 |
| 15 | 0.25 | 45 | 0.75 |
| 20 | 0.33 | 50 | 0.83 |
| 25 | 0.42 | 55 | 0.92 |
| 30 | 0.50 | 60 | 1.00 |
The full table is on the minutes to decimal page. Never type 7:45 as 7.45: that underpays 18 minutes.
Rounding: the 7-minute rule
Many time clocks round punches to the nearest quarter hour. Under federal rules (29 CFR 785.48) this is allowed if it averages out — employees must not lose time over a period. With quarter-hour rounding, 1 to 7 minutes past the quarter round down and 8 to 14 minutes round up:
| Punch | Rounded to the quarter hour |
|---|---|
| 8:07 AM | 8:00 AM |
| 8:08 AM | 8:15 AM |
| 4:52 PM | 4:45 PM |
| 4:53 PM | 5:00 PM |
| 12:22 PM | 12:15 PM |
| 12:23 PM | 12:30 PM |
A payroll week, worked out
Here is one employee’s week of punches, calculated exactly and with quarter-hour rounding:
| Day | In | Out | Break | Exact | Rounded |
|---|---|---|---|---|---|
| Mon | 8:03 AM | 4:58 PM | 30 min | 8:25 (8.42) | 8:30 (8.50) |
| Tue | 7:52 AM | 5:09 PM | 30 min | 8:47 (8.78) | 9:00 (9.00) |
| Wed | 8:08 AM | 5:02 PM | 45 min | 8:09 (8.15) | 8:00 (8.00) |
| Thu | 7:58 AM | 4:37 PM | 30 min | 8:09 (8.15) | 8:00 (8.00) |
| Fri | 8:01 AM | 3:31 PM | 0 min | 7:30 (7.50) | 7:30 (7.50) |
Exact total: 41:00 (41.00 hours). Rounded total: 41:00 (41.00 hours). At $18 an hour the difference is $0.00 this week — rounding must not always go the employer’s way.
Type the same punches into the time card calculator and switch "Round times" between "No rounding" and "Nearest 15 min" to see both totals.
Breaks: what to subtract
- Subtract unpaid meal breaks — usually 30 minutes or more when you are completely relieved of duty.
- Do not subtract short rest breaks of 5 to 20 minutes: federal rules count them as hours worked.
- Some states require meal breaks (for example California: 30 minutes before the end of the 5th hour).
A night-shift week
Night shifts follow the same steps; the only difference is that the end time is on the next calendar day. Most payroll systems count the whole shift on the day it started.
| Shift | Unpaid break | Hours worked | Decimal |
|---|---|---|---|
| 10:00 PM – 7:00 AM | 30 min | 8:30 | 8.50 |
| 10:00 PM – 7:00 AM | 30 min | 8:30 | 8.50 |
| 11:00 PM – 7:30 AM | 45 min | 7:45 | 7.75 |
| 8:00 PM – 6:00 AM | 30 min | 9:30 | 9.50 |
The four shifts add up to 34:15. Night work is not paid extra under federal law, but many employers add a shift differential — and that differential belongs in the regular rate for overtime.
Converting a whole week to decimal
Add the hours:minutes first, then convert once. Days of 7:45, 8:20, 7:55, 8:10 and 6:40 total 38:50 — 38 + 50 ÷ 60 = 38.83 hours. Rounding each day to two decimals first (7.75 + 8.33 + 7.92 + 8.17 + 6.67) gives 38.84: close, but over a year of weeks those cents add up, which is why our calculators convert the total.
Hours in each pay period
| Pay frequency | Pay periods per year | Hours per period (40 h week) |
|---|---|---|
| Weekly | 52 | 40 |
| Biweekly | 26 | 80 |
| Semi-monthly | 24 | 86.67 |
| Monthly | 12 | 173.33 |
Semi-monthly periods (the 15th and the last day of the month) average 86.67 hours, but the real number of workdays in each half month varies between 10 and 12. Overtime is still calculated per workweek, not per pay period, so a semi-monthly payroll has to look at the workweeks inside each period.
Meal-break rules in some states
| State | Meal break |
|---|---|
| California | 30 minutes before the end of the 5th hour; a second one after 10 hours |
| Colorado | 30 minutes for shifts over 5 hours |
| Illinois | 20 minutes for shifts of 7.5 hours or more, within the first 5 hours |
| New York | 30 minutes around midday for shifts over 6 hours |
| Oregon | 30 minutes for shifts of 6 hours or more |
| Washington | 30 minutes for shifts over 5 hours |
Federal law does not require meal or rest breaks at all. If your state requires an unpaid meal break, take it off the day’s total; if the break is paid or you are not fully relieved of duty, it counts as hours worked.
Time that counts as hours worked
- On-call time spent on the employer’s premises, or so restricted that you cannot use it for yourself.
- Required training and meetings, even outside normal hours.
- Travel between job sites during the day (not the normal commute from home).
- Waiting time when you are "engaged to wait" — for example a driver waiting to be loaded.
Employers must keep payroll records for at least three years and time cards for two years under the FLSA. Keep your own copy too: a weekly printout from the time card calculator is enough.
Common mistakes
- Mixing AM and PM: write times in 24-hour format before subtracting.
- Adding decimal and hours:minutes values together.
- Summing rounded daily decimals instead of converting the week’s total — small rounding errors add up.
- Forgetting that a shift past midnight belongs to the day it started in most payroll systems.
Frequently asked questions
How do I calculate my hours worked?
End time minus start time minus unpaid breaks, for each day; then add the days. Convert minutes to decimal by dividing by 60.
What is the 7-minute rule?
When rounding to the nearest quarter hour, 1–7 minutes round down and 8–14 minutes round up.
How many hours is 8:30 to 5:00 with a 30-minute lunch?
8:00 hours.
How do I write 7 hours 45 minutes in decimal?
7.75 hours.
Should I round hours worked?
Only if your employer has a neutral rounding policy, such as to the nearest quarter hour, that rounds both up and down. Many payroll teams now pay exact minutes, which avoids disputes. Your own records should always keep the real punch times.
How do I count a shift that crosses midnight?
Add 24 hours to the end time before subtracting, or let the calculator do it: an end time earlier than the start is read as the next day. Most payroll systems record the whole shift on the day it began.