PTO Accrual Calculator — Days/Year to Hours/Pay Period

Accrual rate versus annual grant

The same "15 days" behaves completely differently depending on which model your employer uses, and this is the thing people discover only when they try to book time off.

An annual grant drops the full balance in at the start of the year, so three weeks in January is available. Accrual earns the balance gradually, so in January only a fraction of it exists. Identical headline number, entirely different practical availability — and a new joiner on an accrual scheme who books a holiday against their stated annual entitlement will find the balance is not there yet.

The arithmetic

The tool computes it one way: annual entitlement in days, multiplied by hours per workday, divided by the number of pay periods in the year.

Using the defaults of 20 days at 8 hours: that is 160 hours a year, and on a biweekly schedule 160 ÷ 26 = 6.15 hours per cycle. The pay-period count is what changes the answer, and the same 160 hours gives:

Biweekly and semi-monthly look interchangeable and are not — 26 periods against 24 produces a different per-period figure from the same entitlement, which is a common source of confusion when someone switches employers.

The hours-worked variant

Some employers accrue per hour actually worked rather than per pay period. Part-time staff then accrue proportionally, and whether overtime hours count depends on policy.

This tool does not support that model. It assumes a fixed number of hours per workday and divides by whole pay periods, so if your employer accrues hourly you will need to work from your expected annual hours instead.

Carryover and caps, where time is actually lost

The per-period rate is the easy part. These three rules determine whether you keep what you earn:

• A cap halts accrual once the balance hits a ceiling. Continuing to work without taking leave then earns nothing — the time is simply forgone, silently.
• Use-it-or-lose-it forfeits the balance at year end. Note that some jurisdictions restrict or prohibit this, treating accrued leave as earned wages, so an identical policy can be lawful in one place and not another.
• Carryover with a limit is the common middle ground, and the practical consequence is that leave needs planning before a cliff rather than after it.

The tool models none of these — it shows what you earn per period in isolation, which is the input to those rules rather than the outcome.

Practical guidance

Check three things in your handbook: the accrual model, the cap, and the carryover rule. All three change what the number means, and the number alone tells you little without them.

Also bear in mind that any projected balance assumes uninterrupted employment and steady hours, and that unpaid leave frequently pauses accrual. This is general information, not legal or HR advice — leave entitlement and whether accrued leave must be paid out on termination vary considerably by country and by US state, and your employer's written policy governs.

Accrued leave is a real liability and a real part of what employment costs, even though it never appears on a payslip. The total compensation builder is where it belongs in the full figure.