How to add up a time card
The arithmetic is simple, but it goes wrong in the same three places every time: minutes get treated like decimals, breaks get forgotten, and overtime gets calculated on the wrong period. Here is the order to work in.
- Convert each punch to a 24-hour clock. A shift from 9:00 to 5:30 is 9:00 to 17:30, which makes the subtraction obvious.
- Subtract the out time from the in time. If the shift crosses midnight, add 24 hours to the out time first — an 8:00 PM to 4:00 AM shift is 20:00 to 28:00, so eight hours.
- Take off unpaid breaks. A 30-minute unpaid lunch turns an 8.5-hour span into 8.0 paid hours.
- Convert minutes to decimal hours. Divide the minutes by 60. Seven hours 45 minutes is 7.75 hours, not 7.45. This single mistake is the most common source of short paychecks.
- Add the days, then apply overtime — not the other way round.
Minutes to decimal hours
The common values are below. For every minute from 1 to 59, both directions, and the rounding rules that go with them, see the full hours and minutes calculator.
| 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 |
Overtime rules
Under the federal Fair Labor Standards Act, non-exempt employees earn overtime at one and a half times their regular rate for hours worked beyond 40 in a workweek. The workweek is a fixed, recurring 168-hour period — it does not have to start on Monday, but once you set it, it stays.
Federal law has no daily overtime requirement. A handful of states do, and the thresholds are not the same:
- California — over eight hours in a day at 1.5×, over 12 hours at double time, plus separate rules for a seventh consecutive workday.
- Alaska — over eight hours in a day at 1.5×.
- Nevada — over eight hours in a 24-hour period, but only for employees earning less than 1.5 times the state minimum wage.
- Colorado — over 12 hours in a day, or 12 consecutive hours, under the COMPS Order. Not eight.
Oregon also requires daily overtime after 10 hours for manufacturing employees. If you are in one of these states, use the daily or combined rule above, and check the current threshold with your state labor office — these change.
Two hours worked in the same week cannot be counted as overtime twice. When both daily and weekly rules apply, hours already paid as daily overtime are excluded before the weekly 40-hour test runs. This calculator does that for you.
Rounding punches
Employers are generally permitted to round clock times to the nearest five, six or fifteen minutes, provided the practice is neutral over time — it must not systematically favour the employer. Rounding that always lands in the company's favour is the version that draws claims.
Some states have moved away from allowing rounding at all where exact times are recorded, California most notably. If your time clock captures precise punches, the safest choice is to pay the exact time and leave rounding off.
Common questions
- Do I have to pay for breaks?
- Short breaks, generally 20 minutes or less, count as paid work time under federal rules. Bona fide meal periods, usually 30 minutes or more where the employee is fully relieved of duty, are unpaid. Enter only the unpaid minutes in the break column.
- How do I handle a shift that crosses midnight?
- Enter it as normal. If the clock out time is earlier than the clock in time, the calculator treats it as the next day and adds 24 hours.
- What is 7 hours and 45 minutes in decimal?
- 7.75 hours. Divide the minutes by 60 — never read the minutes as the decimal.
- Is overtime based on hours worked or hours paid?
- Hours actually worked. Holiday pay, vacation and sick leave are typically not counted toward the 40-hour overtime threshold, because no work was performed. Check your state's rules and your own policy.
- Does this calculator store my times?
- No. Everything runs in your browser and nothing is sent anywhere or saved. Closing the tab clears it.
Other calculators on this site
If the weekly card is not quite what you need:
- Hours and minutes calculator — add up durations you already have, or find the span between two times, with the complete minute-to-decimal conversion chart.
- Military time converter — convert 24-hour times both ways, with the full chart and how each time is spoken.
- Work days in a year — how many work days and hours any year contains once federal holidays and your PTO come out.
And if you are adding up paper cards by hand every pay period, the arithmetic is not really the problem — the collection is. Time tracking apps let staff clock in from a phone and export totals straight to payroll, and most have a free tier for small teams.