How PTO Accrual Works (With Real Examples)

Paid time off "accrues" when employees earn it gradually instead of receiving a full year's worth all at once. If you've ever looked at a pay stub and seen a PTO balance tick up by a few hours every two weeks, that's accrual in action. This guide explains the three common ways PTO is calculated, with worked examples for each.

The three accrual methods

There are really only three models most small teams use, and the right one depends on how predictable your hours are.

• Annual lump sum — the full balance is granted at the start of the year.
• Per pay period — a fixed amount is added each time payroll runs.
• Per hour worked — PTO is earned in proportion to hours, which suits hourly and part-time staff.

Per pay-period accrual

This is the most common method for salaried employees. You take the annual allowance and divide it by the number of pay periods in a year.

So an employee on a 15-day annual policy paid every two weeks earns about 0.58 days of PTO each pay period. By mid-year they've banked roughly 7.5 days.

Per-hour accrual

For hourly teams, PTO is usually earned as a rate per hour worked. A common figure is 0.0385 hours of PTO per hour worked, which adds up to about two weeks a year for someone working full time.

The advantage is fairness: someone who works fewer hours earns proportionally less, and there's no awkward true-up at year end.

Lump-sum allowance

The simplest model: everyone receives their full balance on January 1 (or their work anniversary). It's easy to explain and employees love it, but it carries a small risk — someone could take all their time in January and leave in February. Many teams pair a lump sum with a short waiting period for new hires to manage that.

The trade-off is administrative. Per-hour accrual requires you to know actual hours worked before you can update a balance, so the number moves after payroll rather than on a schedule. For teams with variable shifts that is the only fair method; for salaried staff it is unnecessary precision.

Several states mandate this method for sick leave specifically — one hour per 30 worked in Colorado and Massachusetts, one per 40 in Washington and Illinois — so even a salaried team may end up running per-hour accrual for one bucket.

Lump-sum allowance

The simplest model: everyone receives their full balance on January 1 (or their work anniversary). It's easy to explain and employees love it, but it carries a small risk — someone could take all their time in January and leave in February. Many teams pair a lump sum with a short waiting period for new hires to manage that.

Front-loaded vs accrued PTO works through that risk properly, including how much of it is real.

A full worked example

Take an employee on 15 days per year, paid every two weeks, on an 8-hour standard day, starting 1 March.

1. Annual allowance in hours: 15 × 8 = 120 hours
2. Pay periods per year: 26
3. Accrual per period: 120 ÷ 26 = 4.62 hours
4. Periods worked from 1 March to 31 December: about 22
5. Accrued by year end: 22 × 4.62 = 101.5 hours, or roughly 12.7 days

If your policy front-loaded instead, this person would have received all 15 days on day one despite working ten months. Neither is wrong — but they differ by more than two days, and employees notice.

Four details that decide whether the number is right

Waiting periods

Most policies let new hires accrue from day one but restrict use for the first 30 to 90 days. Several states require exactly this pattern for statutory sick leave. Be explicit about which one you mean: a visible balance that cannot be spent looks like an error to the person looking at it.

Accrual caps

A cap pauses further accrual once a balance reaches a ceiling, usually 1.5× to 2× the annual allowance. It bounds your liability without deleting anything already earned, which matters enormously in states where earned PTO is legally wages. PTO accrual caps covers how to set one.

Rounding

Accrual rarely divides evenly. 120 hours over 26 periods is 4.615384… hours. Rounding each period down costs the employee about half a day a year; rounding up costs you the same. Pick a rule — round to two decimals, or true up in the final period — and apply it consistently.

Unpaid leave

Paid time off usually continues accruing during paid absence, because it is still paid time. Unpaid leave normally pauses it. Say which in the policy, because this is the single most common accrual dispute.

Does PTO accrue on overtime hours?

Under per-pay-period accrual, no — the amount is fixed regardless of hours worked.

Under per-hour accrual, yes, and this surprises employers. Someone working 50-hour weeks accrues 25% faster than someone working 40. Where a state mandates per-hour accrual for sick leave, you cannot cap that within the year, though you may cap carryover into the next.

Common mistakes

That last row is the one that bites hardest, because it surfaces once a year and the damage is already done by the time anyone checks.

Which method should you choose?

If your team is salaried and stable, a lump-sum allowance is the friendliest. If you have turnover or hourly staff, accrual protects the business while still being fair. If any of your staff are in a state with statutory sick leave, you will likely run per-hour accrual for that bucket regardless of what you do for vacation.

Whatever you choose, write it down clearly — ambiguity about how time is earned is one of the most common sources of PTO disputes, and in several states the ambiguity is resolved against whoever drafted the policy.

You can model any of these in seconds with our free PTO accrual calculator, and when you're ready to stop doing this math by hand, SimplyPTO tracks every balance automatically.