How PTO accrual works: the rate, the balance and caps
In short: PTO accrual means you earn paid time off a little at a time: your yearly allowance divided by your pay periods, credited each payday, or a set number of hours for every hour you work. 120 hours a year paid biweekly is 120 / 26 = 4.6154 hours a payday; your balance is what you have earned so far, minus what you have used, less anything a cap or a carryover limit holds back.
How PTO accrual works is simple arithmetic that pay stubs make look complicated. You earn paid time off a little at a time, each payday or for each hour you work, and your balance is what you have earned minus what you have used. The complications are rounding, years with an extra payday, and the two different kinds of limit employers put on a balance. This guide works each one through with real dates, and the PTO accrual calculator does the same arithmetic with your own figures.
The PTO accrual rate: allowance divided by pay periods
Most salaried policies state a yearly allowance and credit it in equal pieces each payday. The PTO accrual per pay period is the allowance divided by the pay periods in a year: 52 for weekly pay, 26 for biweekly, 24 for semi-monthly and 12 for monthly.
| PTO a year | Weekly | Biweekly | Semi-monthly | Monthly |
|---|---|---|---|---|
| 80 hours (10 days) | 1.5385 | 3.0769 | 3.3333 | 6.6667 |
| 120 hours (15 days) | 2.3077 | 4.6154 | 5 | 10 |
| 160 hours (20 days) | 3.0769 | 6.1538 | 6.6667 | 13.3333 |
California's Labor Commissioner uses the same method in its vacation FAQ, where two weeks a year earned week by week comes to 1.538 hours a week. The federal government states its rates per pay period instead. OPM's annual leave fact sheet gives a full-time employee 4 hours each biweekly pay period in the first 3 years, 6 hours from 3 to 15 years with 10 in the last pay period of the year, and 8 hours after that: 104, 160 and 208 hours a year.
PTO accrual based on hours worked
Hourly and part-time policies often credit PTO for each hour worked: 1 hour for every 30 or 40 hours, say. Multiply your hours by the rate. At 1 hour per 30 hours worked, a 40-hour week earns 1.3333 hours and a full year 69.33 hours; a 24-hour week earns 0.8 hours and 41.6 hours a year. One hour per 30 is California's paid sick leave accrual method, and its paid sick leave FAQ lets an employer cap the total accrued at 80 hours or 10 days. OPM uses the same idea for part-time federal staff: 1 hour for each 20 hours in a pay status in the first 3 years.
Why your pay stub does not show 80 / 26
80 hours biweekly is 3.0769 hours a payday, which does not fit in the two decimals most pay stubs show. Payroll systems handle it in one of three ways. Rounding every payday up to 3.08 credits 80.08 hours a year; cutting to 3.07 credits 79.82; rounding the running total instead, as the calculator does, alternates 3.08 and 3.07 and lands on exactly 80.00 after 26 paydays. A few hundredths a year is nothing, but it explains why a balance never quite matches your own multiplication.
A bigger difference comes from the calendar. A year has 52 weeks and one or two days, so a biweekly payroll sometimes has 27 paydays in one calendar year. Paydays every other Friday from January 1, 2027 fall 27 times in 2027, the last on December 31. If the policy credits 80 / 26 hours every payday, that calendar year credits 27 x 3.0769 = 83.08 hours. Some employers accept that; others use 80 / 27 in such a year, or count the allowance per leave year rather than per calendar year. Your handbook says which.
Accrual caps and carryover limits are different rules
Employers limit balances in two ways, and they behave very differently.
A cap, or maximum balance, stops accrual while you are at the limit. Take 120 hours a year, paid biweekly from January 1, 2026, a 180-hour cap and 170 hours already banked. The paydays on January 14 and 28 bring the balance to 179.23, the February 11 payday adds only 0.77 to reach 180, and the next eight paydays add nothing: 36.15 hours never earned. A 24-hour vacation on May 26 drops the balance to 156, and accrual resumes on the next payday. Nothing already earned is taken away.
A carryover limit takes away whatever is above it when a new year starts, which is what use it or lose it means. Same employee, same rate, starting 2026 at zero: 26 paydays credit exactly 120 hours, a week off in July (40 hours) and three days around Thanksgiving (24 hours) use 64, and the balance on December 31 is 56. With a 40-hour carryover limit, 16 hours disappear on January 1, 2027, and by January 31 the balance is back up to 49.23. You can open this example in the calculator and change the dates or the limit.
Federally there is no rule either way, since the Fair Labor Standards Act does not require paid vacation at all, so state law and the written policy decide. California is the strictest. Its vacation FAQ says a use it or lose it policy is illegal there, and it draws the line between the two kinds of limit plainly:
Unlike "use it or lose it" policies, a vacation policy that places a "cap" or "ceiling" on vacation pay accruals is permissible.
Federal employees work under the opposite kind of rule. Their carryover ceiling is 30 days (240 hours) for staff stationed in the United States, and OPM's annual leave fact sheet is direct about the excess: it says any accrued annual leave above the ceiling will be forfeited if not used by the final day of the leave year.
Checking your own balance
- Find the rate and the schedule. The handbook gives the allowance or the per-hour rate; the pay stub shows how often you are paid.
- Count the paydays since your balance was last right, not the weeks. Semi-monthly pay credits 24 times a year, on the 15th and the last day of the month; biweekly pay credits 26 or, in some calendar years, 27.
- Subtract the time you took on the dates you took it, before applying a cap, because time off is what makes room under a cap.
- Apply the limits in order: a carryover cut on the first day of the new year, then the year's paydays.
The PTO accrual calculator follows exactly these steps, lists every payday and day off with the running balance, and copies the schedule as CSV for a spreadsheet. To count how many working days a stretch of leave covers, without the federal holidays inside it, use the business days calculator.
Questions people ask
What does accrued PTO mean?
Accrued PTO is the paid time off you have earned so far but not yet used. If you get 80 hours a year and are halfway through the year with no time taken, you have accrued about 40 hours. Front-loaded PTO is the opposite: the whole year's allowance is put in your balance on day one.
Do you accrue PTO while you are on PTO?
Usually yes, because paid time off is paid time, but it depends on the policy. For federal employees OPM says that during annual leave they are in pay status and continue to accrue annual and sick leave. Private employers set their own rule, often counting paid hours rather than hours worked.
Is unused PTO paid out when you leave a job?
Federal law does not require it; the Department of Labor treats vacation pay as a matter of agreement between employer and employee. Some states do: California's Labor Commissioner says all earned and unused vacation must be paid at the final rate of pay when employment ends. Check your state and your written policy.
When does PTO start accruing for a new hire?
Most policies start accrual on the first day or the first full pay period, and some add a waiting period before you can use it. California only recognizes a period with no vacation if no vacation is really earned in it, not as a way of moving the first year's time to the second. Enter your first full pay period as the start date in the calculator.
Esta guía también está en español: Cómo se acumulan las vacaciones en Estados Unidos (PTO).
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