The difference in one table
| Every two weeks | Twice a month | |
|---|---|---|
| Pay dates a year | 26 (sometimes 27) | Always 24 |
| Interval | Exactly 14 days | 15 or 16 days, varying |
| Lands on | The same weekday every time | The same dates, any weekday |
| Typical dates | Every other Friday | 15th and last day |
| Contains whole workweeks | Yes — exactly two | No |
Why the workweek point matters most
A biweekly period contains exactly two workweeks. Overtime is calculated within each, and both close inside the period, so the arithmetic is clean.
A semimonthly period does not align with workweeks at all. Fifteen days is two weeks and a day, so workweeks routinely straddle the boundary. The employer must still calculate overtime on the whole workweek — which means part of it lands in one pay period and part in the next.
The practical result: if you are paid semimonthly, overtime often arrives on the following cheque rather than the one covering the days you worked. This is normal and correct, and it is the source of a great deal of confusion. What is not correct is splitting a workweek at the pay-period boundary and applying the 40-hour threshold to each fragment — that suppresses overtime and is a genuine violation.
The 27th payday
Twenty-six periods of fourteen days is 364 days. A year is 365, or 366 in a leap year. That leftover day accumulates, and roughly every eleventh year a biweekly schedule produces 27 paydays in one calendar year.
For hourly staff nothing unusual happens — it is another period worked and paid. For salaried staff it forces a decision, because an annual salary was divided by 26:
- Divide by 27 instead, making every cheque slightly smaller. Accurate over the year and unpopular in January.
- Pay the 27th anyway, absorbing roughly 3.8% extra salary cost.
- Pay 26 and hold the extra, which creates its own problems and can breach state pay-frequency rules.
The organisations that handle it badly are the ones that discover it in November. The payroll calendar generator will show you a 27-payday year in advance — generate the next few years and look at the count.
Which is better
For employees paid hourly: biweekly, usually. Periods are equal, overtime resolves inside the period it belongs to, and cheques are predictable in size.
For salaried employees: semimonthly gives an identical amount every time, which suits monthly budgeting. Biweekly gives two months a year with three paydays, which people either love or find confusing.
For the employer: semimonthly means fewer payroll runs and clean alignment with monthly accounting, at the cost of harder overtime handling. Biweekly is simpler for hourly workforces and is the most common private-sector arrangement in the US.
Some states also restrict the choice — a few require at least semimonthly payment for certain workers, so monthly is not always available.
Weekends and holidays
Semimonthly schedules hit weekends constantly, because the 15th and the last day of the month fall on whatever weekday they land on. Biweekly schedules, anchored to a weekday, only move when a holiday intervenes.
In both cases the near-universal convention is to pay on the previous business day. Paying early is safe; paying late can breach state pay-interval rules.
Related
- What a workweek is, and why it decides your overtime
- Generate a payroll calendar for any year
- Daily and weekly overtime, and the trap between them