PunchSemi-Monthly Payroll and Overtime: Why Twice-a-Month Pay Splits the Workweek (2026)
Semi-Monthly Payroll and Overtime: Why Twice-a-Month Pay Splits the Workweek (2026)
The short answer: Semi-monthly payroll pays employees twice a month, usually on the 15th and the last day. Those pay periods do not line up with workweeks, and the FLSA still requires overtime to be paid by the workweek. You cannot use the pay-period total to decide who is owed overtime. A single seven-day workweek often straddles the 15th-to-16th boundary, and if you split its hours across two checks, a workweek that earned overtime can look like two short weeks that earned none. That is an underpayment, and it is the most common overtime mistake on a semi-monthly schedule. Punch tracks hours by the workweek no matter when you cut checks, so the overtime is counted before the pay period ever splits it.
If you run payroll on the 15th and the end of the month, this is the one rule that quietly costs owners the most. It is worth twenty minutes to understand.
Semi-Monthly Is Not Biweekly
The two sound similar and behave very differently.
Biweekly pay means every two weeks. You get 26 paychecks a year, and every pay period is exactly 14 days, which is precisely two seven-day workweeks. A biweekly period always contains two whole workweeks.
Semi-monthly pay means twice a month, on fixed calendar dates like the 15th and the last day of the month. You get 24 paychecks a year, and each pay period is 15 or 16 days long. That length is the problem. Fifteen or sixteen days is more than two workweeks but less than three, so a semi-monthly pay period does not contain a whole number of workweeks. It cuts through the middle of one.
Semi-monthly is popular because it is predictable for accounting. The dates never drift, and salaried budgets divide cleanly into 24. But payroll convenience and overtime law are two separate things, and the calendar that makes semi-monthly easy to budget is the same calendar that breaks overtime math.
The Workweek Is the Only Unit That Counts
Federal overtime does not care about your pay schedule. It cares about the workweek.
Under 29 CFR 778.105, a workweek is a fixed and regularly recurring period of 168 hours, which is seven consecutive 24-hour days. You choose when it starts. Many employers use Sunday at midnight or Monday at midnight. Once you set it, it stays fixed, and it applies the same way every week regardless of when you pay.
Overtime is owed for every hour past 40 in that workweek, at one and one half times the regular rate. And each workweek stands on its own. The Department of Labor is explicit that there can be no averaging of two or more workweeks. A 50-hour week followed by a 30-hour week is 10 hours of overtime, not an 80-hour "wash." The 30-hour week does not erase the overtime the 50-hour week earned.
Nothing about paying twice a month changes this. The DOL confirms that an employer may pay wages in semi-monthly installments without any problem, as long as overtime is still computed on a workweek basis. The installment schedule is fine. Averaging across it is not.
The Trap: One Workweek, Two Paychecks
Here is where semi-monthly payroll goes wrong in practice.
Picture an employee paid $20 an hour. The workweek runs Sunday through Saturday. Pay periods run the 1st through the 15th and the 16th through the end of the month.
Now take a workweek that falls across the split, say Sunday the 14th through Saturday the 20th. The 14th and 15th land in the first pay period. The 16th through the 20th land in the second. The employee works 44 hours in that workweek.
Those 44 hours are one workweek. Four of them are overtime, because 44 is four past 40. The overtime is real and it is owed.
But watch what a pay-period system does to it. It sees 16 hours in the first check (Sunday and Monday, the 14th and 15th) and 28 hours in the second check (Tuesday through Saturday, the 16th through the 20th). Sixteen is under 40. Twenty-eight is under 40. So a system that totals each pay period sees two ordinary part-weeks and reports zero overtime. The employee just lost four hours of premium pay, worth $40 that week, and nothing on the paycheck shows it was ever there.
Multiply that by a crew and by every straddling workweek across a year, and it becomes exactly the kind of back-pay claim the DOL collects on. The agency can recover up to two years of unpaid overtime, three years if the violation was willful, and courts can add liquidated damages equal to the amount owed. A quiet rounding of the workweek boundary turns into a real bill.
The reverse trap exists too. Because a semi-monthly period spans more than two workweeks, an employee could rack up a high pay-period total, 90-plus hours, and owe no overtime at all if the hours were spread so no single workweek passed 40. The pay-period total tells you nothing on its own. Only the workweek does.
Salaried Nonexempt Staff: Convert the Salary First
If you pay a salaried employee who is still owed overtime, semi-monthly adds one more step. You have to turn the salary into an hourly regular rate before you can calculate anything.
The FLSA gives the exact conversion in 29 CFR 778.113. A semi-monthly salary is translated to its weekly equivalent by multiplying by 24 and dividing by 52. A monthly salary is multiplied by 12 and divided by 52. Then you divide the weekly figure by the hours it is meant to cover to get the regular rate.
The regulation's own example: a semi-monthly salary of $780 for a 40-hour week works out to $780 times 24, which is $18,720 a year, divided by 52, which is $360 a week, divided by 40, which is a regular rate of $9 an hour. If that employee works a 46-hour workweek, the six overtime hours are paid at one and one half times $9, which is $13.50, for an added $81 that week on top of the salary.
Notice that the calculation happens at the workweek level even though the salary arrives twice a month. The salary is a payment schedule. The regular rate and the overtime are still weekly.
What Your Records Actually Have to Show
To pay a semi-monthly schedule correctly, your time records need to do something a calendar-based payroll export cannot do on its own. They have to preserve the workweek.
That means every workweek's total is computed as a whole seven-day figure, even when the week is split between two pay periods. The overtime is determined on that whole-week total. Then, and only then, the resulting pay is assigned to the correct check. A workweek that starts in one pay period and ends in the next is still one workweek for overtime purposes, and the record has to prove you treated it that way.
Doing this by hand on a spreadsheet is where errors creep in. Someone sums the columns inside each pay period, the straddling week gets chopped, and the overtime disappears. The safest approach is a system that never lets the workweek get cut in the first place.
How Punch Keeps the Workweek Intact
Punch is built around the workweek, which is the boundary semi-monthly payroll tends to erase.
Employees punch in and punch out from their phones, with lunch tracked separately. Every punch lands inside a fixed seven-day workweek that you set for the whole organization. Overtime is calculated against that workweek using the correct 40-hour threshold, or the daily and weekly thresholds for the state or country you operate in, drawn from Punch's overtime presets for more than 50 countries. A workweek that straddles the 15th is still one workweek in Punch. Its hours are added together and its overtime is counted before anything is assigned to a pay period.
Punch runs weekly and biweekly pay periods natively, and managers approve hours with per-shift review or bulk approve and reject. When you run semi-monthly payroll in your accounting system, Punch gives you the piece that calendar-based payroll misses: accurate per-workweek totals, with overtime already applied, in owner and manager Reports you can export to Excel or push straight into QuickBooks Online. You feed correct workweek numbers into your semi-monthly run instead of hoping the split did not swallow an overtime hour.
Verification stays honest and stays private. Punch confirms a punch with a job-site geofence on iOS, never a camera in your crew's face. There is no facial recognition and no photo at a punch. Punches also work offline, so a workweek in a basement or a cell dead zone still records cleanly and syncs when signal returns.
Pricing is flat per organization. Every plan includes every feature, owners are always free, and you are not billed per seat, so adding the crew members whose straddling workweeks caused the problem does not raise the price.
The Bottom Line
Semi-monthly payroll is a fine way to schedule checks. It is a dangerous way to think about overtime. The pay period runs on the calendar. Overtime runs on the workweek, and the two do not line up. Count overtime by the seven-day workweek, convert salaries with the multiply-by-24, divide-by-52 rule, and never let a pay-period boundary split a workweek in half.
Start with Punch and let the workweek stay whole, so twice-a-month payroll never costs you an overtime hour you did not know you skipped.
This article is general information, not legal advice. Overtime rules vary by state and country, and some states add daily overtime and other requirements on top of the federal rules described here. Confirm your obligations with a qualified professional for your jurisdiction.