What an accrual rate is and why plans use one
An accrual rate is the small quantity of paid leave you earn per unit of service — per hour worked, per pay period, or occasionally per month. Employers use accrual rather than a lump grant for two reasons. It matches the benefit to service actually rendered, so someone who leaves in March has earned about a quarter of the year's leave rather than all or none of it. And it keeps the balance sheet honest: accrued leave is a liability, and accruing it gradually spreads the expense across the year rather than dumping it in January.
The two methods produce the same annual total and different mid-year balances. A per-pay-period plan credits the same number of hours every payday regardless of what you worked, which suits salaried staff. A per-hour-worked plan credits a fraction of an hour for each hour on the clock, which suits variable schedules and part-time staff because it scales automatically — a half-time employee accrues half as much without anyone maintaining a separate schedule.
Where the two diverge is at the edges. Take an unpaid week and a per-period plan still credits you; a per-hour plan does not. Work 50 hours in a week and a per-hour plan may or may not credit the extra ten, depending on whether the policy counts overtime hours. That policy detail is worth reading, because over a year of steady overtime it is the difference between 120 and 132 hours of leave.
Nothing in federal law requires paid vacation at all. The Fair Labor Standards Act sets no minimum, so accrual rates, caps and payout rules come from the employer's policy and, increasingly, from state law.
Deriving the rate, and what a cap actually does
Start by putting the grant into hours, because that is the unit balances are kept in. Fifteen days on an eight-hour shift is 120 hours; the same fifteen days on a twelve-hour shift is 180 hours, which is why the hours-per-day field matters as much as the days field.
For the per-hour rate, divide annual PTO hours by annual scheduled hours: 120 ÷ 2,080 = 0.057692 hours of leave for every hour worked. The number looks tiny, which is exactly why it is easy to mis-key on a payroll setup screen — an accrual rate entered as 0.0577 instead of 0.057692 costs about 0.04 hours a year, but one entered as 0.05769 to five places is fine. Prefer four decimal places or more.
For the per-period rate, divide annual PTO hours by pay periods: 120 ÷ 26 = 4.615385 hours each biweekly payday. Semimonthly plans give tidier numbers because 24 divides more grants evenly — the same 120 hours is exactly 5.0000 per semimonthly period.
A cap is where policies differ most, and the distinction matters financially. A hard cap stops accrual once the balance reaches the limit: you earn nothing further until you take leave and drop below it. A use-it-or-lose-it rule zeroes or trims the balance at a fixed date instead. This calculator models the hard cap, clamping the balance at the limit and reporting the hours that could not be added. Several states, California among them, prohibit use-it-or-lose-it forfeiture of earned vacation entirely while permitting a reasonable accrual cap — the legal theory being that earned vacation is wages you have already worked for, and wages cannot be taken back, but an employer may decline to grant more.
The payout leg is simple arithmetic — balance times hourly rate — but note which rate. Accrued leave is normally valued at the rate in force when it is paid, not when it was earned. That means a balance carried through a raise is worth more than it was, which is one reason employers cap balances rather than letting them grow.
Worked example: 15 days, biweekly pay, halfway through the year
Your plan grants 15 days a year, a PTO day is 8 hours, you are paid biweekly, 13 paydays have passed, you have taken 40 hours of leave, your cap is 240 hours and you earn $30.00 an hour.
- Annual grant in hours. 15 days × 8 h = 120 hours.
- Per-hour accrual rate. 120 ÷ 2,080 = 0.057692 hours per hour worked.
- Per-period accrual rate. 120 ÷ 26 = 4.615385 hours per payday.
- Accrued to date. 4.615385 × 13 = 60.00 hours. Note the cross-check: 13 of 26 periods is half the year, and half of 120 is 60.
- Balance before the cap. 0 carried in + 60.00 accrued − 40.00 used = 20.00 hours.
- Cap test. 20.00 is well below 240, so nothing is clamped and no hours are lost.
- Balance in days. 20.00 ÷ 8 = 2.50 days.
- Cash value. 20.00 × $30.00 = $600.00.
Confirm the per-hour method agrees. Thirteen biweekly periods at 40 hours a week is 13 × 80 = 1,040 hours worked, and 0.057692 × 1,040 = 60.00 hours — the same answer, because 1,040 is exactly half of 2,080. The two methods only separate when actual hours differ from the schedule.
Now project forward. With 13 periods left and no further usage, you will add another 4.615385 × 13 = 60.00 hours, ending the year at 80.00 hours or 10 days. If your plan allows a 40-hour carryover and you are still holding 80 hours in December, 40 of them are at risk — a concrete reason to book leave in the autumn rather than discover the problem in January.
Accrual rates for common PTO grants
| Annual grant | Hours per year | Per hour worked | Per biweekly period | Per semimonthly period |
|---|---|---|---|---|
| 10 days | 80 | 0.038462 | 3.0769 | 3.3333 |
| 12 days | 96 | 0.046154 | 3.6923 | 4.0000 |
| 15 days | 120 | 0.057692 | 4.6154 | 5.0000 |
| 20 days | 160 | 0.076923 | 6.1538 | 6.6667 |
| 25 days | 200 | 0.096154 | 7.6923 | 8.3333 |
| 30 days | 240 | 0.115385 | 9.2308 | 10.0000 |
For a part-time employee, replace 2,080 with actual annual scheduled hours in the per-hour column; the per-period columns assume a full-time grant and must be prorated separately.
Reading your balance and spotting a plan problem
Compare the accrual figure on your stub against the per-period rate here. If they match to four decimal places, the plan is set up correctly and any balance difference comes from usage timing. If the stub rate is lower, the two usual causes are a probationary period during which accrual is credited but not available, and a per-hour plan excluding overtime and paid leave from the accrual base.
Watch the cap rather than the balance. A balance approaching the cap is the only situation in which PTO can be lost outright, and it arrives quietly: accrual simply stops, and nothing on the stub announces it. If the projection table shows the balance flattening before the end of the year, the flat section is unearned leave, and every pay period spent there costs you the per-period accrual amount. On a 15-day plan that is 4.62 hours a period, or about $138 at a $30 rate.
The payout figure has a specific meaning that depends entirely on your state. In California, Illinois, Massachusetts and several others, accrued vacation is treated as earned wages and must be paid out on separation; in many other states it is payable only if the employer's policy says so. Sick leave is usually treated differently from vacation even in payout states, which is one argument for plans that keep the two buckets separate rather than combining them into a single PTO bank.
Note that a payout is taxed as supplemental wages, not as a windfall. A $4,500 balance paid out is subject to federal income tax withholding, Social Security and Medicare in the period it is paid — often at the flat 22% supplemental withholding rate, which is not the same as your marginal rate. The gross to net paycheck calculator shows the effect on the check itself.
Assumptions this calculator makes
- Accrual is linear. Real plans often step the rate at service anniversaries, so a mid-year promotion from 15 to 20 days is not modelled. Run the calculator twice and add the two segments.
- The cap is a hard cap. The balance is clamped and the excess is reported as lost. Plans with a use-it-or-lose-it date rather than a running cap behave differently.
- Usage is netted before the cap is applied. That matches most systems, but a few apply the cap at accrual time rather than at period end.
- Carryover has already been trimmed. Enter the balance that survived last year's carryover limit, not the balance before it.
- One PTO bank. Plans that keep vacation and sick leave separate, with separate caps and separate payout rules, need one run per bank.
- No waiting period. Many plans accrue from day one but block usage for 90 days; that affects when you can book leave, not what you have earned.
- The payout rate is current pay. Balances are normally valued at the rate in force when paid, so a raise increases the value of hours earned earlier.
State law can override your employer's policy
Paid time off is governed by state law, not federal law, and the differences are large. California treats earned vacation as wages: it cannot be forfeited, must be paid out on separation, and a use-it-or-lose-it policy is unenforceable, though a reasonable accrual cap is permitted. Several other states also mandate payout of accrued vacation on termination. Many states have separate paid sick leave statutes with their own accrual rates — commonly one hour per 30 hours worked — that run alongside a PTO plan and cannot be reduced by it. Check your state's labour department before assuming a company handbook is the last word.
Where the accrual number comes from and what it costs
For an employer, PTO is not free time — it is a wage cost recognised as it is earned. Fifteen days of leave on a 2,080-hour schedule is 120 ÷ 2,080 = 5.77% of payroll, which is a bigger number than most people expect and sits alongside the 7.65% employer FICA charge that the FICA payroll tax calculator quantifies. Adding a day of PTO to a 15-day plan therefore costs about 0.38% of payroll a year, and the accrued liability that day creates persists until it is taken or paid.
That liability is also why caps exist. An uncapped plan lets balances compound across years and revalue upward with every raise, and a long-tenured workforce can accumulate a payout obligation worth several percent of annual payroll. Capping at one and a half or two times the annual grant — 180 or 240 hours on a 15-day plan — bounds the exposure while still allowing an employee to bank a long trip.
For an employee, the useful framing is that PTO is deferred compensation you have already worked for. Converting the balance to a cash figure makes that concrete, and it changes two decisions. First, whether to take leave rather than let it sit: hours above the cap are worth nothing, so their real value is zero and taking them is free. Second, whether an offer with more PTO is better than one with more salary. Five extra days on a $30 hourly rate is 40 hours × $30 = $1,200 a year of value, which you can compare directly against a salary difference using the salary to hourly rate calculator — though remember that time off also raises your effective rate per hour actually worked, so the benefit is worth slightly more than its cash value suggests.