PTO Accrual Calculator

Biweekly and semi-monthly are not the same thing

This is the single most common mistake in paid time off math, and it is entirely a vocabulary problem. Biweekly means every two weeks: a paycheck every 14 days, which lands 26 times in a 365-day year. Semi-monthly means twice a month, usually on the 15th and the last day, which lands 24 times. People use the two words interchangeably. Payroll does not.

The gap is 26 ÷ 24, or 8.33%. If your policy grants 4 hours per pay period, biweekly gives you 104 hours a year and semi-monthly gives you 96. That is a whole extra workday, invented or destroyed by reading the wrong word off a handbook. Any calculator that offers a single "twice a month" option is quietly picking one of the two for you.

A related detail: because 26 × 14 is 364 days, biweekly payroll drifts by a day a year and occasionally produces a calendar year with 27 pay dates. That is why this tool counts actual dates between your start and target rather than dividing an annual figure — an extra period is real money in hours, and an annual average would hide it.

Three ways employers write the same rate

Accrual policies are written in whichever unit was convenient to whoever wrote the handbook, and they are not interchangeable without knowing your schedule.

• Per hour worked. The most common form for hourly staff and the form nearly every US sick leave statute uses — typically one hour earned for every 30 hours worked. It is proportional by construction, so it needs your weekly hours to mean anything. Someone at 20 hours a week accrues exactly half of what a 40-hour colleague does on identical terms. Overtime hours usually count toward accrual too, which is why a heavy quarter can push your balance ahead of the projection.
• Per pay period. A flat number of hours each paycheck. Simple to read, and the form where the biweekly/semi-monthly confusion does its damage, because the annual total depends entirely on how many paychecks there are.
• Per month or per year. A salaried convention. Ten hours a month is 120 hours a year regardless of how often you are paid, but it becomes 4.62 hours in a biweekly period and exactly 5 in a semi-monthly one. The tool converts through the annual figure, which is the only common denominator that survives the switch.

Full-time in the US is conventionally 2,080 hours a year, so a policy of 0.0385 hours per hour worked is a hair over 80 hours — ten days — for someone at 40 hours a week, and something quite different for anyone else.

The accrual cap is a silent leak

An accrual cap sets a maximum balance. When you reach it, accrual stops. The hours you would have earned are not deferred, not banked, not paid — they are never credited at all, and no line on your pay stub says so. This is the mechanic that separates a useful calculator from a decorative one, and it is why the tool simulates every pay period instead of multiplying at the end.

Sitting at the cap is not a full bucket. It is an open drain. An employee capped at 240 hours who accrues 4 hours biweekly and takes no time off discards 104 hours over a year — thirteen workdays of compensation that were earned and then evaporated. The calculator reports the exact date the cap is reached and the running total lost after it, because that number is the one that actually changes behaviour.

Timing matters more than most people expect. Taking 40 hours off in January opens 40 hours of headroom that then absorbs five pay periods of accrual; taking the same 40 hours in December absorbs nothing, because the cap was already discarding accrual all year. Same time off, same policy, 40 hours of difference. Switch the "when they come off" selector to see it.

Carryover, rollover and use-it-or-lose-it are three policies

A cap limits your balance at all times. A carryover rule only bites once a year, at the plan year boundary, and there are three distinct versions of it that people describe with the same words:

• Full carryover. The balance crosses the boundary untouched. The cap is then the only real constraint.
• Limited carryover. Anything above a threshold — 40 or 80 hours are typical — is forfeited on day one of the new year. The rest survives.
• Use it or lose it. The balance resets to zero. Every hour not taken by the deadline is gone.

The plan year is not always January. Anniversary-based plans, fiscal years starting in July or October, and academic years are all common, and moving the boundary moves which accrual is at risk — so the tool asks for the month rather than assuming.

Use-it-or-lose-it is also the policy most likely to be unenforceable where you live. States that treat accrued vacation as earned wages — California, Colorado, Montana, Nebraska and Massachusetts among them — generally prohibit outright forfeiture while still permitting a reasonable accrual cap, on the logic that a cap stops you earning more but never takes back what you earned. The distinction sounds legalistic and is worth real money.

Hours only become days once you pick a workday

Balances are tracked in hours; time off is requested in days; the bridge between them is your daily schedule, and it is not always eight hours. A compressed four-day week runs 10-hour days. A 37.5-hour week runs 7.5. Part time runs 4, 5 or 6. Nurses and shift workers run 12.

A 120-hour balance is 15 days at eight hours and 12 days at ten. Nothing about the balance changed — only how much time off you believe you have, which is exactly the belief people plan holidays around. The tool asks for the workday length instead of hardcoding it, and shows the answer in both units at once.

Accrued PTO is not a front-loaded grant

Some employers deposit the full annual allowance on day one of the plan year. That is a grant, not an accrual, and it behaves differently: you can take all of it in February, but if you leave in March many policies claw back or refuse to pay the unearned portion. Accrual is the opposite — you can only spend what has already vested, but what has vested is generally yours.

To model a grant here, set the balance to the full allowance and the accrual rate to zero. To model the hybrid that many companies actually run — a front-loaded grant that then accrues nothing until the next reset — do the same and set carryover to whatever the reset rule is.

Check it against your pay stub, not against a blog post

Everything above is how policies usually work, not how yours certainly works. Two numbers on your own documents settle it: the accrual line on your pay stub, which tells you the real per-period figure including any tenure-based step increases, and the balance shown in your HR portal, which is your true starting point. Enter those and the projection is about your plan rather than about the average plan.

US federal law requires no paid time off whatsoever. There is no FLSA minimum for vacation, holidays or personal days. Everything you have is granted by your employer's policy and shaped by state law, which means the handbook is the source of truth and this tool is an arithmetic engine for whatever the handbook says.

Privacy

Every calculation runs in your browser. Your balance, your rate, your schedule and your planned time off are never uploaded, never logged and never stored, and there is no account. That matters here because an accrual balance combined with a workweek is a fairly precise description of your employment — the kind of thing that should not need to leave the machine to be divided by twenty-six.