Time Card Calculator

How the time card calculator works

A time card records when someone started and stopped work. Turning those clock times into payable hours means four steps, and one of them is where most mistakes happen.

1. Convert each clock time to minutes from midnight. 09:00 is 540, 17:00 is 1020. Working in minutes avoids the arithmetic errors that come from handling hours and minutes separately.
2. Subtract the start from the end. 1020 − 540 = 480 minutes. If the answer is zero or negative, the shift crossed midnight, so add 1440 minutes (a full day).
3. Subtract unpaid breaks. A 30-minute unpaid lunch on that shift leaves 450 minutes. Only unpaid time belongs here — short rest breaks are paid under federal rules.
4. Divide by 60 to get decimal hours. 450 ÷ 60 = 7.5 hours. That decimal number is what payroll multiplies by the hourly rate.

The calculator does all four steps for every row, totals the week, and then splits the total into regular and overtime hours at the threshold you set.

The rules behind the numbers

Decimal hours, not hours and minutes

Payroll systems multiply a rate by a decimal number of hours. That is why 7 hours 30 minutes must become 7.50, not 7.30. The conversion is minutes divided by 60: 30 minutes is 0.50, 15 minutes is 0.25, 45 minutes is 0.75, and 6 minutes is 0.10. Writing 7.30 for seven and a half hours understates the shift by 0.2 hours, and across a year that error compounds into real money.

Which breaks are unpaid

Under the Fair Labor Standards Act, rest periods of five to twenty minutes are hours worked and must be paid — they cannot be deducted. A bona fide meal period of at least 30 minutes, during which the employee is completely relieved from duty, may be unpaid. A working lunch is paid. If an employee is asked to answer the phone or watch the desk while eating, the time counts.

This is the single most common source of pay disputes, and it usually runs in the employee's favour when a claim is filed. Enter only genuinely unpaid time in the break column.

Overtime is a weekly test

The federal rule is straightforward: hours worked beyond 40 in a workweek are paid at one and a half times the regular rate. The workweek is any fixed and regularly recurring period of 168 hours — seven consecutive 24-hour periods. It does not have to start on Sunday or Monday, and it does not have to match your calendar.

What matters is that the test is applied to the week, not the day. Ten hours on Monday and six on Tuesday is sixteen hours, and no federal overtime is due. A few states layer a daily rule on top: California requires overtime past eight hours in a day, Alaska past eight, and Nevada past eight in most cases.

Paid time off is not hours worked

Holiday pay, vacation pay and sick pay are not counted when measuring whether someone passed 40 hours worked. An employee who works 38 hours and takes a paid holiday for 8 does not reach 46 hours for overtime purposes — the threshold is measured against the 38 worked hours.

Rounding

Some payroll systems round to the nearest quarter hour or tenth of an hour. Federal rules allow rounding only if it does not systematically favour the employer over time — a policy that always rounds arrivals down and departures up is unlawful. This calculator does no rounding at all: it works to the minute and converts at the end.

Three worked examples

1. A standard 40-hour week with a 30-minute lunch

Monday to Friday, 09:00 to 17:00, with a 30-minute unpaid lunch each day. Each day is 1020 − 540 = 480 minutes, minus 30 for lunch, which is 450 minutes or 7.50 hours. Five identical days give 37.50 hours and no overtime. Gross pay at $22 an hour is $825.00.

This is the example that catches people out. An eight-hour working day that includes an unpaid lunch is a 7.5-hour paid day, so a "40-hour week" with daily unpaid lunches is really 37.5 paid hours.

2. A week that runs into overtime

Same schedule, but Thursday runs long to 19:00 and Friday to 18:00. Thursday becomes 1020 − 540 to 1140 − 540, that is 570 minutes less 30, or 9.00 hours. Friday is 510 minutes less 30, or 8.00 hours. The week totals 37.50 + 1.50 + 0.50 = 39.50 hours — still under the threshold, so no overtime despite two long days.

Now add a six-hour Saturday shift. The week reaches 45.50 hours, of which 40.00 are regular and 5.50 are overtime. At $22 an hour that is $880.00 regular plus $181.50 overtime, a gross of $1,061.50. The Saturday hours are what triggered the split, not the long Thursday.

3. An overnight shift

A support rota runs 22:00 to 06:00 with a 30-minute unpaid break. The end time is earlier than the start, so the calculator adds a full day: 360 + 1440 − 1320 = 480 minutes, less 30 for the break, giving 7.50 hours. Four such shifts are 30.00 hours.

Watch the workweek boundary here. If the workweek starts on Monday and a shift begins at 22:00 on Sunday and ends at 06:00 on Monday, the hours may need to be split between two workweeks depending on how the employer defines it. Most employers assign the entire shift to the day it started, but the rules differ and it is worth confirming in writing.

Five mistakes to avoid

1. Writing 7.30 for seven and a half hours. Minutes are not hundredths. 30 minutes is 0.50. This single error understates a shift by 12 minutes and repeats every day.
2. Deducting a break that was actually worked. If the phone rang or the desk had to be covered, the meal period was not bona fide and federal rules say it must be paid.
3. Applying the overtime test daily instead of weekly. Under federal law a ten-hour Monday does not create overtime on its own. Assuming it does overpays; assuming weekly when your state has a daily rule underpays.
4. Counting paid leave toward the 40 hours. Holiday, vacation and sick hours are not hours worked and do not push someone into overtime.
5. Running two weeks at once. Entering 80 hours across a fortnight and expecting a clean answer breaks the weekly overtime test. Run each week separately.

Sources and standards

FAQ

How do I calculate my hours from a time card?

Write down the clock-in and clock-out time for each day, convert each to minutes from midnight, subtract the start from the end, then subtract any unpaid break. Divide by 60 to get decimal hours. Monday 09:00 to 17:00 with a 30-minute lunch is 7.5 hours, not 8.

How does the calculator handle a shift that crosses midnight?

If the end time is earlier than the start time the calculator treats it as the next day and adds 24 hours. 22:00 to 05:00 becomes 7 hours rather than a negative number. This is the standard convention for night shifts and for nursing or security rotas.

When does overtime start?

In the United States the FLSA requires one and a half times the regular rate for hours worked beyond 40 in a workweek. The workweek is any fixed and regularly recurring period of 168 hours — it does not have to be Monday to Sunday, and an employer may define it as, for example, Wednesday to Tuesday.

Is overtime calculated per day or per week?

Under the FLSA it is per workweek. Twelve hours on Monday and six on Tuesday is eighteen hours for the week and no federal overtime is due. A few states including California, Alaska and Nevada add a daily overtime rule on top.

Are lunch breaks paid?

It depends on length and whether you are free from duties. Rest breaks shorter than about 20 minutes count as hours worked and must be paid. Bona fide meal periods of 30 minutes or more, during which you are completely relieved of duty, may be unpaid. Enter only genuinely unpaid time in the break column.

What is a workweek and can my employer change it?

A workweek is a fixed, regularly recurring 168-hour period — seven consecutive 24-hour periods. The FLSA does not require it to match the calendar week, and an employer may change it if the change is intended to be permanent.

Why is the overtime rate 1.5 and not 2?

The FLSA sets the federal minimum at one and a half times the regular rate. Double time comes from a contract, a collective bargaining agreement or state law rather than federal requirement, though some employers and several states offer it beyond twelve hours in a day or on the seventh consecutive day.

Does the calculator round my hours?

It works to the nearest minute and displays hours and minutes, so 7 hours 52 minutes reads as 7h 52m. It does not apply the quarter-hour or tenth-of-an-hour rounding some payroll systems use. Federal rules allow rounding only if it does not systematically deprive employees of pay over time.

Are holiday or vacation hours part of overtime?

Generally no. Paid time off is not hours worked, so it is not counted when deciding whether you passed 40 hours. If you are paid 40 worked hours plus 8 holiday hours, the threshold is measured against the 40 worked hours.

Can I use this for a two-week pay period?

Yes, but run it twice. Overtime is assessed per workweek, so entering 80 hours over two weeks would produce the wrong split. Calculate week one and week two separately, then add the results.