Free Workweek-Boundary Overtime Calculator for Pay Periods

Page last updated 25 Oct 2026

How to use the workweek boundary overtime calculator

Set the day and time your payroll’s workweek starts, the overtime threshold, and the pay-period type: semi-monthly, biweekly, weekly or monthly.
Paste rows with employee, date, start, end and an optional unpaid break, or just date and hours, or load a CSV.
Add an hourly rate if you want the overtime premium, which is the extra half-time.
Read the table by workweek and the table by pay period, and compare with the wrongly pro-rated column.

How is overtime counted across pay periods?

Every shift is placed in a fixed workweek that starts on the day and time you choose, with shifts split at midnight and at the workweek start and unpaid breaks taken off. In each workweek, the hours after the threshold, 40 by default, are overtime. The hours are then allocated to pay periods: straight time to the period in which it was worked, and the overtime premium to the payday of the period in which the workweek ends. A pro-rated column shows the common mistake.

For example, an employee works Monday to Friday, 26 to 30 October, from 8:00 to 18:30 with a 30-minute unpaid break, and 4 hours on Saturday 31 October. The Monday-start workweek runs to 1 November and has 54.00 hours: 40.00 regular and 14.00 overtime. All the hours are worked in the 16 to 31 October pay period, but the workweek ends on 1 November, so the overtime is generally due on the payday for the 1 to 15 November period. The names and hours are made up; yours come from what you type.

Who should use the workweek boundary overtime calculator

Payroll staff on semi-monthly or monthly schedules, where pay periods rarely match workweeks
Employees checking whether overtime for a split week was paid on the right payday
Anyone who needs to see why dividing 40 hours across a pay period gives the wrong answer

Who should not use this

Employees in states with daily overtime, who also need the California tab on the overtime rate page or their own state rules
Hospital 8 and 80 schedules, police and fire work periods, union contracts or exempt staff
Anyone who wants overlapping rows found; run the duplicate checker first

Limitations

Federal weekly rule only: more than the threshold in a fixed workweek.
Hours-only rows are placed at the workweek start time on that date; use start and end times when a shift crosses the boundary.
Breaks are taken from the end of each shift when a shift is split, which only matters when the boundary falls inside a shift.
It is arithmetic, not a legal determination.
Nothing is uploaded or stored on a server. Clearing your browser data also removes the saved profile.

Calculate overtime by workweek, not just pay period

Use this workweek overtime calculator to see overtime across two pay periods, when a pay period ends mid-week or a workweek spans two pay periods. Each workweek is a fixed, repeating 168-hour period and each one stands alone: hours are not averaged between weeks and the length of your pay period does not move the 40-hour line (29 CFR 778.104). When a pay period ends in the middle of a workweek, the arithmetic still starts with the workweek.

Set your workweek start day and time

Pick the day and time your payroll's workweek starts. Changing it can change who has overtime: five 10-hour days from Saturday to Wednesday are 50 hours in one Saturday-start workweek but 20 and 30 hours in two Monday-start workweeks.

Enter shifts across pay-period boundaries

Paste rows with employee, date, start, end and optional unpaid break, or just date and hours. Choose semi-monthly, biweekly, weekly or monthly pay periods; for weekly and biweekly give the first day of any pay period. A sample file can be downloaded under the calculator.

See regular and overtime hours

Two tables per employee: by workweek (hours, regular, overtime, which pay periods the week touches) and by pay period (hours worked, overtime worked in the period, overtime due on that period's payday). Add an hourly rate to see the overtime premium (the extra half-time).

Worked example: A workweek split across two paychecks

Ana works Monday to Friday, Oct 26-30, 8:00 to 18:30 with a 30-minute unpaid break (10 hours a day), and 4 hours on Saturday, Oct 31. The workweek (Monday start) runs Oct 26 to Nov 1.

Worked example: A workweek split across two paychecks
	Hours
Total in the workweek	54.00
Regular (first 40)	40.00
Overtime	14.00
Overtime worked in the Oct 16-31 period	14.00
Overtime due on the Nov 1-15 payday (the period in which the workweek ends)	14.00

Prorating 40 hours across the 16-day period would give 0.00 overtime hours: the wrong answer.

Federal rules and state-specific caveats

This tool applies the federal weekly rule only: more than 40 hours (or the threshold you set) in a fixed workweek. It does not apply state daily overtime, double time, seventh-day rules, the 8-and-80 hospital system, public-safety work periods, union contracts or exemptions. It also assumes the hours you enter are hours worked and paid. It is arithmetic, not a legal determination. For official guidance see the U.S. Department of Labor overtime page and your state labor agency.

Sources and review

Reviewed on 25 Oct 2026 against the published sources below. Rules and prices change, so check the current position before you rely on a figure.

Common questions

Is overtime calculated by pay period or workweek?

By workweek. Under the Fair Labor Standards Act each workweek stands on its own: a fixed, repeating period of 168 hours (seven 24-hour days) that does not have to match the calendar week or the pay period (29 CFR 778.104 and 778.105). Pay frequency changes when you are paid, not when overtime starts.

How do you calculate overtime when a pay period ends midweek?

Put every hour in its fixed workweek first. In each workweek, hours after the 40th are overtime, in the order they were worked. Then allocate: the overtime premium for a split workweek is generally due on the regular payday for the pay period in which that workweek ends (29 CFR 778.106). Example: Ana works Mon-Fri 10 hours plus 4 on Saturday, a 54.00-hour week from Oct 26 to Nov 1. The 14.00 overtime hours are worked in the Oct 16-31 period but the week ends on Nov 1, so they are due with the Nov 1-15 period's payday.

Can overtime hours be averaged across two workweeks?

No. If someone works 30 hours one week and 50 the next, the 10 hours over 40 in the second week are overtime even though the two weeks average 40 (29 CFR 778.104). The tool shows this: in its calculation for 80.00 hours over two weeks of 30 and 50, overtime is 10.00 hours, not zero.

How do you calculate overtime for semi-monthly payroll?

Semi-monthly periods (1st-15th and 16th-end of month) have different lengths and rarely line up with workweeks, so never divide 40 hours by period length. Compute overtime for each fixed workweek, then assign the hours and the overtime to the periods as described above. The "wrongly pro-rated" column in the tool shows how far off a pro-rated threshold can be.

What if a workweek crosses two pay periods (a workweek spans two pay periods)?

Count the whole workweek as one unit for overtime. The straight-time hours belong to the pay periods in which they were worked, and the overtime premium is generally due on the payday for the period in which the workweek ends. The tool marks such weeks as "split" and shows both views. Employers sometimes pay differently, and state rules can differ.

Does biweekly payroll change the 40-hour overtime rule?

No. Federal overtime is still over 40 hours in each workweek, not over 80 in two weeks. The main exceptions are hospitals and residential care facilities that use the 8-and-80 system (see the 8 and 80 calculator) and certain public-safety work periods.

How do I set the workweek start day for overtime?

The employer chooses a fixed, recurring 168-hour workweek that can begin on any day and hour, and it stays the same regardless of schedule. It can be changed only if the change is meant to be permanent and is not made to avoid overtime (29 CFR 778.105). Use the start day your payroll actually uses; if you are an employee, ask payroll or check your policy. This is general information, not legal advice.

Does this work for California or other states with daily overtime?

It applies the federal weekly rule only. Some states, California among them, also require daily overtime and have their own rules, which this tool does not apply. For California daily and double-time hours use the California tab of the overtime rate adjustment calculator.

What about unpaid breaks and overnight shifts?

Enter an unpaid break in minutes and it is deducted from the shift. A shift that crosses midnight, or crosses the moment the workweek starts, is split at that moment so each part lands in the right workweek.

Is it safe to upload payroll CSV data to an online tool?

With this tool nothing is uploaded: the file is read and compared in your browser and the code makes no network request with your data (you can confirm in the Network tab of your browser's developer tools). That is a statement about this tool only. Many other online tools do send files to a server, so check each one's privacy policy before you use real payroll data. Never paste Social Security numbers or bank details into any comparison tool; employee IDs and hours are enough.

Guides that explain the rules

Related tools

This tool produces a document from the information you type. It does not give legal, tax or accounting advice, and it does not check that your figures or rates are right. See the disclaimer. Found a mistake? Report an error in a calculation.