Convert clock times into paid hours, handle breaks and shifts that cross midnight, and check gross pay before a paycheck goes out. Flags the 4 mistakes that most often produce a plausible-but-wrong answer.
Key takeaways
- Convert minutes by dividing by 60, so 45 minutes is 0.75 hours and not 0.45.
- Add 24 hours when the end time is earlier than the start, so night shifts come out right.
- Apply the break rule your workplace actually uses, paid or unpaid, before you deduct anything.
- Overtime multiplies the hourly rate for the overtime hours only, and the rules vary by place.
- Gross pay is before deductions, so the deposit will be smaller.
A time card turns two clock times into one number
A shift is a start and an end. Subtract the start from the end to get the span, subtract any unpaid break, and you have the hours worked. The arithmetic looks trivial, but it goes wrong in three places: minutes that do not fit a decimal, shifts that cross midnight and breaks that are paid in some workplaces and unpaid in others.
Why payroll uses decimal hours
Multiplying a rate by 7.75 is simple, and multiplying it by 7 hours 45 minutes is not. Payroll systems therefore store time as decimal hours. The conversion divides the minutes by 60, so 15 minutes is 0.25, 30 is 0.50 and 45 is 0.75. Seven hours and 45 minutes is 7.75 hours, and reading it as 7.45 underpays the worker by a quarter of an hour.
Turning decimal hours back into a clock time
The reverse takes the whole part as hours and multiplies the remainder by 60. Seven and three quarter hours is 7 hours and 45 minutes. Do this whenever a payroll figure needs to be compared with a clock, an appointment or a schedule. Multiply by 60, never by 100, because there are 60 minutes in an hour.
Shifts that cross midnight
A night shift from 10:00 PM to 6:00 AM has an end time earlier than its start on the clock, which breaks a plain subtraction. The fix is to add 24 hours when the end is earlier than the start, so the span is eight hours. Two identical times read as zero hours, not as a full day, which is a rule worth stating in any timekeeping policy.
Unpaid breaks and paid breaks
Some workplaces deduct meal periods and pay for short rest breaks, and others treat every break the same. Check the policy before you deduct anything. A calculator subtracts whatever break you enter, so the result is only as right as the rule you apply. A break longer than the shift never goes below zero worked hours.
Rounding rules change the total
Some employers round each punch to the nearest quarter hour. Rounding the start and the end separately can move the total either way, and over a pay period the differences can add up. A written, consistent rule protects both sides, and an unrounded calculation is the honest baseline to compare against.
Overtime multiplies the rate, not the hours
Overtime hours are paid at a higher multiplier of the base rate, commonly time and a half. At $22 an hour, 6 overtime hours at 1.5 times add $198 on top of the regular pay. Which hours count as overtime is set by law and by contract, and it differs by place, so use the rule that applies to you.
From gross pay to a paycheck
Gross pay is the total before any deduction. At $22 an hour with 40 regular hours and 6 overtime hours, a period earns $1,078, and over 26 periods that is $28,028 a year. Taxes, insurance and retirement contributions come out afterward, so the deposit is smaller. Use gross pay to check the hours, and a paycheck estimate to plan spending.
Pay periods and annual figures
The number of pay periods a year changes the annual total for the same per-period pay. Twenty-six biweekly periods and 24 semimonthly ones differ by about 8 percent. When you convert a period figure to a yearly one, use the schedule your employer actually follows, and remember that some years have 27 biweekly paydays.
Keep records that support the number
Whatever the method, keep the raw punches, the break rule and the rounding policy alongside the result. A pay question is settled fastest with the underlying times. A calculator is a check on the arithmetic, and the record is what settles a disagreement.
Worked with real numbers
What this looks like in the time card calculator
The guidance above is easier to judge against figures. Using the time card calculator worked example, moving start time from 8:00 AM to 10:00 AM changes the hours worked from 7.00 to 9.00.
| Start time | Hours worked | Pay for the shift | Minutes worked |
|---|---|---|---|
| 8:00 AM | 9.00 | $180 | 540 |
| 8:30 AM | 8.50 | $170 | 510 |
| 9:00 AM | 8.00 | $160 | 480 |
| 9:30 AM | 7.50 | $150 | 450 |
| 10:00 AM | 7.00 | $140 | 420 |
Open the Time Card Calculator to use your own numbers →
The inputs behind those figures
| Input | Value | Definition |
|---|---|---|
| Start time | 9:00 AM | Enter the start time used in this calculation. |
| End time | 5:30 PM | Enter the end time used in this calculation. |
| Unpaid break (minutes) | 30 | Enter the unpaid break (minutes) used in this calculation. |
| Hourly rate | $20 | Enter the hourly rate used in this calculation. |
What goes wrong
Common mistakes
Each of these produces an answer that looks reasonable, which is why they survive review. To catch them in time cards, decimal hours and overtime explained, rerun the time card calculator with a different assumption and check whether the result moves in the direction the guidance predicts, since an error that survives that test is usually in one of the inputs and not in the arithmetic.
| The mistake | Why it misleads | Do this instead |
|---|---|---|
| Typing 7 hours 45 minutes as 7.45 | The digits after the decimal are a fraction of an hour, so 7.45 is 7 hours 27 minutes and underpays by 18 minutes. | Divide the minutes by 60 and add them to the hours. |
| Subtracting the hour numbers only | Ignoring the minutes gives 8 hours for a shift that runs 8 hours 15 minutes. | Convert both times to minutes or use a calculator that keeps the minutes. |
| Treating a midnight shift as a negative span | The end time is earlier on the clock, so a plain subtraction returns a negative number. | Add 24 hours when the end is earlier than the start. |
| Applying overtime to all hours | Only the hours over the threshold carry the higher multiplier, and using it for every hour overstates the pay. | Multiply the overtime multiplier by the overtime hours alone. |
People also ask
Frequently asked questions
How do I convert minutes to a decimal for payroll?
Divide the minutes by 60. Fifteen minutes is 0.25 hours, thirty is 0.50 and forty-five is 0.75. Add the result to the whole hours.
How do I convert decimal hours back to hours and minutes?
Take the whole number as the hours and multiply the decimal part by 60 to get the minutes. Seven and three quarters is 7 hours and 45 minutes.
How do I calculate hours for a shift that crosses midnight?
Add 24 hours to the end time when it is earlier than the start time, then subtract. A 10 PM to 6 AM shift is eight hours.
Should unpaid breaks be subtracted from hours worked?
Yes if the break is unpaid under your workplace's rules. Some rest breaks are paid, so check the policy before you deduct.
How is overtime pay calculated?
Multiply the regular hourly rate by the overtime multiplier, commonly 1.5, and by the overtime hours. Add it to the pay for the regular hours.
Why is my paycheck smaller than my gross pay?
Taxes, insurance premiums and retirement contributions come out of gross pay before the deposit.
How many hours is 8:30 AM to 4:45 PM?
Eight hours and 15 minutes, which is 8.25 in decimal hours. The time duration calculator shows both.
Do I round my punches to the quarter hour?
That depends on the employer's written policy. Rounding each punch separately can move the total in either direction, so an unrounded calculation is the honest baseline to compare against.
How many pay periods are in a year?
Weekly pay has 52, biweekly has 26 and sometimes 27 paydays, semimonthly has 24 and monthly has 12. Use the schedule your employer follows when you convert a period figure to a yearly one.
If I double unpaid break (minutes) in the time card calculator, does the hours worked double?
Doubling it from 30 to 60 takes the hours worked from 8.00 to 7.50, which is 0.94 times the worked-example figure. So it falls instead of rising. Halving it to 15 gives 8.25.
How much does unpaid break (minutes) matter in the time card calculator?
The worked example uses 30. With the other inputs left at the worked example, moving unpaid break (minutes) from 27 to 33 takes the hours worked from 8.05 to 7.95, a swing of 1.3% of the worked-example figure.