Time Card Calculator

The time card calculator turns a repeated weekly schedule into total paid hours, regular hours, overtime hours, and a daily breakdown. It is practical for employees checking a timesheet, managers planning coverage, freelancers documenting billable time, and payroll reviewers who want to verify that lunch deductions and overnight shifts were handled consistently.

Weekly time-card inputs

Start by turning on the days worked. The default pattern is Monday through Friday, but Saturday and Sunday can be included and any weekday can be turned off. Enter the daily start hour and minute, then the daily end hour and minute, using 24-hour time. A 9 AM start is 09:00; a 5 PM end is 17:00. If the shift crosses midnight, enter the next clock time normally, such as 22:00 to 06:00.

Next decide whether lunch should be deducted. When include lunch break is on, the lunch duration is subtracted from every selected day. The lunch start hour and minute are used to print a lunch note, so they help communicate the assumed meal period, but the current the calculation function does not validate that lunch falls inside the shift. Finally, set the weekly overtime threshold. The default is 40 hours, which matches the common federal Fair Labor Standards Act weekly overtime threshold for many nonexempt U.S. employees, but your situation may require a different number.

For a single shift, use the shift calculator. For elapsed time with seconds, use the time duration calculator. For pay conversion after you know the hours, the hourly wage calculator and overtime calculator can help estimate earnings.

Exact formula used by the calculation

The calculator first converts start and end clock fields into decimal hours:

$\text{clock hours} = \text{hour} + \frac{\text{minute}}{60}$

Daily hours are calculated as end minus start. If that value is zero or negative, the calculation adds 24 hours so the shift is treated as an overnight shift.

$\text{day hours before lunch} = \begin{cases}\text{end} - \text{start}, & \text{if end} - \text{start} > 0 \\\text{end} - \text{start} + 24, & \text{if end} - \text{start} \le 0\end{cases}$

If lunch is enabled, the lunch duration in minutes is divided by 60 and subtracted:

$\text{paid day hours} = \text{day hours before lunch} - \frac{\text{lunch minutes}}{60}$

The weekly overtime split is sequential. For each selected day, Monday through Sunday, the calculation checks how many regular hours remain before reaching the threshold. It assigns the smaller of daily hours and remaining regular capacity to regular time, then assigns the rest of that day to overtime.

$\text{regular today} = \min(\text{paid day hours},\ \max(0,\ \text{threshold} - \text{regular so far}))$

$\text{overtime today} = \max(0,\ \text{paid day hours} - \text{regular today})$

Total hours equal regular plus overtime. If paid day hours become negative after the lunch deduction, the calculation shows a validation message rather than a misleading total.

Checked example

Assume Monday through Friday are selected, start time is 09:00, end time is 17:00, lunch is included, lunch duration is 60 minutes, and the overtime threshold is 40 hours. The clock span is 17 - 9, or 8 hours. Lunch subtracts 60 divided by 60, so paid day hours are 7.00.

The calculator processes five selected days. Monday adds 7 regular hours, Tuesday reaches 14, Wednesday 21, Thursday 28, and Friday 35. Because the regular total never exceeds the 40 hour threshold, overtime is 0.00. The primary result is 35.00 total hours, with 35.00 regular hours, 0.00 overtime hours, and 7.00 hours per selected day. The note says the shift is 09:00-17:00 across five selected days and that lunch runs 12:00-13:00.

Change the same schedule to six selected days and the sequence matters. The first five days still total 35 regular hours. On Saturday, only 5 regular hours remain before the 40 hour threshold, so Saturday contributes 5 regular and 2 overtime hours. The weekly result becomes 42.00 total hours, 40.00 regular, and 2.00 overtime.

Interpretation and payroll cautions

The U.S. Department of Labor states that covered nonexempt employees generally must receive overtime pay at not less than one and one-half times the regular rate for hours over 40 in a workweek, but this calculator does not determine coverage, exemptions, rates, or state-specific rules. Some states or industries use daily overtime, split shifts, meal penalties, paid rest breaks, or special rounding rules. The calculator also assumes each selected day has the same start, end, and lunch settings; it is not a punch-clock replacement.

Use the result to catch arithmetic errors before payroll closes. Compare the daily breakdown with your own records. If your workplace rounds punches to 5, 6, or 15 minute increments, enter the rounded times only if that is the official record. If a shift starts in one workweek and ends in another, ask how your payroll system allocates the hours, because this calculator treats the shift as one repeated daily block.

Edge cases and common mistakes

Midnight crossover is handled, but dates are not displayed. A Sunday 22:00 to Monday 06:00 shift appears under whichever weekday switch you selected; it is your responsibility to place it in the correct payroll week. Daylight saving transitions are not modeled. A real shift during the spring-forward hour may have fewer elapsed minutes, while a fall-back shift may have more. For cross-zone work, convert times with the time-zone calculator before entering the local schedule.

Common mistakes include leaving lunch enabled when lunch is paid, using 12 for midnight instead of 00, forgetting that the same daily time applies to every selected day, and treating the result as legal advice. Keep source time records, especially if the numbers affect wages.

Clock and date boundaries

Each row uses local clock readings without a calendar date or time zone. An end earlier than its start is treated as crossing midnight into the next date. Daylight-saving gaps or repeated hours are not adjusted, and Gregorian leap days do not change the arithmetic because dates are absent. For payroll on a DST transition, use the employer’s dated time-zone records and rounding policy.

Sources

• U.S. Department of Labor, Fact Sheet #22: Hours Worked Under the FLSA — federal guidance on hours worked, meal periods, waiting time, and related wage-hour topics.
• U.S. Department of Labor, Overtime Pay — overview of the federal weekly overtime standard.
• U.S. Department of Labor, Fact Sheet #53: The Health Care Industry and Hours Worked — examples of hours-worked issues in shift-heavy workplaces.