PTO Accrual by Pay Period: Biweekly vs. Semimonthly
Under a pay-period policy, PTO is added each time a pay period ends. If the policy states an annual amount, that amount is divided by the number of pay periods in the year, so the same yearly PTO gives a different amount per paycheck depending on whether you are paid biweekly or semimonthly. A policy can also state a fixed number of hours per period, in which case the yearly total depends on how many pay periods the year has.
Biweekly and semimonthly are not the same
The two schedules sound alike but produce a different number of paychecks:
- Biweekly pay arrives every 14 days. That is 26 pay periods in most years, and 27 in some.
- Semimonthly pay arrives twice a month, commonly on the 15th and the last day. That is always 24 pay periods.
Because 26 is larger than 24, a biweekly employee earns a slightly smaller amount per paycheck from the same annual allowance, but receives it more often.
The same 80 hours, two different rates
Synthetic example. A policy grants 80 hours of PTO a year.
| Schedule | Pay periods | Per period | Final period | Year total |
|---|---|---|---|---|
| Semimonthly | 24 | 3 h 20 min | 3 h 20 min | 80 h |
| Biweekly | 26 | 3 h 04 min | 3 h 20 min | 80 h |
Semimonthly divides evenly: 80 hours is 4,800 minutes, and 4,800 ÷ 24 = 200 minutes, or 3 h 20 min every pay period. Biweekly does not: 4,800 ÷ 26 is 184.6 minutes, which cannot be paid out exactly in whole minutes.
Rounding and the final-period adjustment
A common way to keep the annual total exact is to round each period down and add the leftover minutes to the last pay period of the year. With 26 periods, each period gets 184 minutes (3 h 04 min). Twenty-five periods add up to 4,600 minutes, so the last period gets the remaining 200 minutes (3 h 20 min), and the year totals exactly 80 hours.
Other policies round each period to the nearest minute or to a fixed number of decimals and accept a small difference at year end. Check how your policy handles it; the methodology explains the method LeaveTools uses.
Years with 27 biweekly pay periods
A year has 52 weeks plus one day (two in a leap year), so biweekly pay dates slowly shift through the calendar. When the first pay period of a calendar policy year ends on January 1 in a common year, or on January 1 or 2 in a leap year, that year has 27 biweekly pay period end dates instead of 26.
A policy can handle this in different ways. It might spread the annual amount over 27 periods, so each period is smaller and the year still totals the same. Or it might keep a fixed amount per period, so the employee simply receives one extra accrual that year. Which approach applies is a decision in the employer's policy. The LeaveTools calculator supports both: choose annual hours spread across pay periods for the first and fixed hours per pay period for the second.
Try it
Open the PTO accrual calculator and enter:
- Pay period frequency: Biweekly, first pay period end date 2026-01-09.
- How PTO accrues: Annual hours spread across pay periods, annual PTO hours 80.
- Start date 2026-01-01, end date 2026-12-31, starting balance 0.
The ledger shows 25 accruals of 3.07 hours and a final accrual of 3.33 hours. Change the first pay period end date to 2026-01-01 to see a 27-period year and its notice.
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Reviewed by José Luis Pérez on