What is a work hours calculator?
A work hours calculator is a simple tool that turns your daily clock-in and clock-out times into a weekly total — with unpaid lunch breaks subtracted and overtime pay calculated automatically. Instead of doing the mental math across seven days (and remembering to deduct each lunch), you type in your times and the tool does it instantly.
Hourly workers use it to check that their paycheck matches the hours they actually worked. Managers use it to sanity-check timesheets before payroll. Freelancers and part-time workers use it to track billable time across a week. And anyone working more than 40 hours uses it to see exactly how much overtime pay they should expect, calculated at the standard time-and-a-half rate.
This calculator goes beyond a plain hours counter: it separates your week into regular hours and overtime hours, then applies your hourly rate to each. That means the number at the bottom — total pay — already includes your overtime premium, so what you see is a realistic estimate of your gross weekly pay.
The formula behind the math
The calculation is straightforward and happens in three stages:
- Day hours = Clock-out − Clock-in − Lunch. Your shift length in hours, minus your lunch break converted from minutes to hours. A 9-hour shift with a 30-minute lunch is 9 − 0.5 = 8.5 paid hours.
- Weekly overtime = max(Total hours − 40, 0). Anything above 40 hours in the week counts as overtime; anything at or below 40 counts as zero overtime.
- Overtime pay = Overtime hours × Hourly rate × 1.5. Regular pay is regular hours × hourly rate, and total pay is the two added together.
For example, if you work 45 hours at $20 per hour, your regular pay is 40 × $20 = $800 and your overtime pay is 5 × $20 × 1.5 = $150, for a total of $950.
Worked example
Let's walk through a typical week. On Monday you clock in at 9:00 AM and clock out at 5:30 PM, with a 30-minute lunch. The shift is 8.5 hours, minus 0.5 hours of lunch = 8.0 hours for Monday.
Repeat that across the week and suppose your daily totals are: Monday 8.0, Tuesday 8.5, Wednesday 8.0, Thursday 8.5, Friday 8.0, Saturday 1.0, Sunday 0. That's 42 total hours. The first 40 are regular hours; the remaining 2 hours are overtime.
At $20 per hour: regular pay = 40 × $20 = $800, and overtime pay = 2 × $20 × 1.5 = $60. Total pay = $860. The calculator above runs this exact math on every keystroke, so you can adjust any day and watch the totals update immediately.
How to use this calculator
- Enter your hourly rate at the top of the tool. This is your gross rate before taxes and deductions.
- For each day you worked, enter your clock-in time and clock-out time using the time pickers. The lunch break defaults to 30 minutes — change it to your actual unpaid break (use 0 if you had none).
- Check the per-day hours shown on the right of each row. Leave days you didn't work blank; they count as zero.
- Read the summary cards below the grid: total hours, regular hours, overtime hours, and each corresponding pay amount.
- Use the Clear button to wipe the whole week and start fresh.
What about overnight shifts?
Night-shift workers clock out on the following calendar day — for example, clocking in at 10:00 PM and clocking out at 6:00 AM. This calculator handles that automatically: whenever your clock-out time is earlier than (or equal to) your clock-in time, it adds 24 hours, so 10:00 PM → 6:00 AM correctly counts as 8 hours before lunch is deducted. Just enter your real times in order; there's no special toggle needed.
One caveat: because this is a weekly (not biweekly) calculator, a shift that crosses midnight still counts toward the day you clocked in. For most weekly pay estimates that's fine, but always defer to your employer's pay-period rules for official payroll.
A note on rounding and employer policies
This tool calculates your exact hours, down to the minute. Some employers round time entries to the nearest quarter hour (15 minutes) for payroll, which can make your official paycheck differ by a few minutes from the number here. Rounding policies must be neutral over time under federal rules — they can't consistently shortchange you — but it's worth knowing why your stub might read 7.75 hours when the calculator shows 7.72.
Also keep in mind that this calculator assumes a standard 40-hour overtime threshold at time-and-a-half. Your state may add extra rules (California, for example, requires overtime after 8 hours in a single day and double time after 12). This page is an estimate for planning and double-checking, not payroll or legal advice.
Frequently asked questions
Is overtime always after 40 hours?
Under the US federal Fair Labor Standards Act (FLSA), yes for non-exempt employees: overtime pay at 1.5 times the regular rate kicks in after 40 hours in a workweek. But some states add daily overtime rules — California, for example, requires overtime after 8 hours in a single day — so check your state's labor rules too.
How do lunch breaks affect my total hours?
Unpaid lunch breaks are subtracted from your day: clock-out time minus clock-in time minus lunch time. A 30-minute lunch turns an 8.5-hour shift into 8 paid hours. This calculator subtracts the lunch minutes you enter for each day automatically.
How do I handle overnight shifts?
If your clock-out time is earlier than your clock-in time, this calculator treats it as an overnight shift and adds 24 hours — so 10:00 PM to 6:00 AM counts as 8 hours. Just enter your real times; the math handles the rest.
Are salaried employees eligible for overtime?
It depends. Some salaried employees are classified as exempt and do not earn overtime, but salaried non-exempt employees can still earn overtime for hours over 40 in a week. Your classification depends on your job duties and salary level under the FLSA — ask your employer or HR department if you are unsure.
Is this calculator free to use?
Yes. TimeTally Tools is completely free with no sign-up. All calculations run in your browser, and your entries are never sent to a server.
Related tools
- Time Card Calculator — fill out a weekly time card with per-day hours and total gross pay.
- Overtime Calculator — enter total weekly hours directly to compute time-and-a-half pay.
- Salary to Hourly Calculator — convert an annual salary into an equivalent hourly rate.
- Tip Calculator — split bills and figure out tips in seconds.