Time Card Calculator guide
How to Calculate Work Hours and Decimal Time
Calculate work hours from clock-in and clock-out times, subtract unpaid breaks, handle overnight shifts, and convert minutes to decimal hours.
Use the Time Card CalculatorQuick answer
The basic work-hours formula
Subtract clock-in from clock-out, then subtract unpaid break time. Perform the calculation in minutes first; that avoids confusing clock notation with decimal notation.
Worked minutes = clock-out minutes − clock-in minutes − unpaid break
A shift from 08:30 to 17:00 lasts 510 minutes. After a 30-minute unpaid break, worked time is 480 minutes: 8 hours, or8.00 decimal hours.
Worked examples
Standard, overnight, and split shifts
| Shift | Clock time | Unpaid break | Worked time |
|---|---|---|---|
| Standard | 08:30–17:00 | 30 min | 8h 0m |
| Overnight | 22:00–06:00 | 30 min | 7h 30m |
| Split, part 1 | 08:00–12:00 | 0 min | 4h 0m |
| Split, part 2 | 13:00–17:30 | 0 min | 4h 30m |
For an overnight shift, add 24 hours when clock-out is earlier than clock-in. For a split day, calculate each shift separately and add the results. This prevents the gap between shifts from being counted as work.
Total a complete week
Add seven days, unpaid breaks, overnight work, and second shifts.
Decimal conversion
Convert minutes to decimal hours
Decimal hours express the minutes as a fraction of 60. They are not the digits that appear after the colon on a clock. For example, 7:30 means seven hours and 30 minutes, while 7.30 decimal hours means seven hours and 18 minutes.
Decimal hours = whole hours + minutes ÷ 60
| Minutes | Decimal | Minutes | Decimal |
|---|---|---|---|
| 5 | 0.08 | 30 | 0.50 |
| 10 | 0.17 | 40 | 0.67 |
| 15 | 0.25 | 45 | 0.75 |
| 20 | 0.33 | 50 | 0.83 |
Add daily minutes before rounding when possible. Rounding every shift separately can make the weekly total slightly different from converting the complete weekly minute total once.
Weekly totals
Add a week and interpret a threshold
Add the worked minutes for every shift, then divide the final minute total by 60. A threshold such as 40 hours can divide the total into minutes below and above that number, but it is only a mathematical split.
Avoid bad totals
Common time-card mistakes
- Reading 7:45 as 7.45 hours: 45 minutes is 0.75 of an hour, so the decimal value is 7.75.
- Forgetting midnight: a clock-out earlier than clock-in normally indicates the following day, not a negative shift.
- Counting a split-shift gap: calculate the two working periods separately.
- Subtracting paid breaks: only subtract break time that should be excluded under the applicable timekeeping policy.
Quick answers
Frequently asked questions
How do I calculate an overnight shift?
Treat the clock-out time as occurring on the following day. For example, 22:00 to 06:00 is eight hours before subtracting any unpaid break.
What is 7 hours 45 minutes in decimal hours?
It is 7.75 decimal hours. Divide 45 minutes by 60 to get 0.75, then add the seven whole hours.
Are all hours above 40 automatically overtime?
Not necessarily. Overtime eligibility and pay depend on the worker, employer policy, pay period, and applicable law. A time calculator can show hours above a chosen threshold but cannot determine legal entitlement or wages.