If you offer paid time off, at some point you have to answer a deceptively simple question: how does an employee earn it? That mechanism is called PTO accrual, and getting it right is the difference between a leave policy people trust and a spreadsheet nobody can reconcile.
This is PTO accrual explained in plain English — the three common ways paid time is earned (monthly, per hour worked, and an annual lump-sum grant), the settings that shape each one, and how a balance is spent when leave gets approved.
What “accrual” actually means
Accrual is just the rule that turns time — either time worked or time elapsed — into a growing balance of paid hours an employee can later take off. Two things happen over the life of a policy: hours are earned and hours are drawn (subtracted when approved leave is taken).
Almost every serious PTO system tracks the balance in hours rather than days, because hours divide cleanly across part-timers, overtime, and odd shift lengths.
In Punchwell, this is handled by a built-in leave and PTO accrual engine: you define a leave type, mark it paid or unpaid, and choose how it accrues. Everything below describes choices that engine gives you — but the concepts apply to any tool, so this is worth understanding before you configure anything.
The three accrual methods
There are three common ways to earn PTO. Most policies use exactly one of them per leave type.
1. Monthly accrual
The employee earns a fixed number of hours each month, regardless of exactly how many hours they worked. For example, a policy might grant a set number of hours on the first of every month, so the balance climbs steadily across the year.
Who it suits: salaried staff and predictable full-timers whose schedules don’t vary much. It’s simple to explain and easy for people to plan around.
2. Per-hour-worked accrual
The balance grows in proportion to actual hours on the clock. A common pattern is to earn a small fraction of an hour of PTO for every hour worked — so someone who picks up extra shifts earns PTO faster, and someone who works fewer hours earns less.
Who it suits: hourly, shift, and part-time teams where hours genuinely vary week to week. It’s the fairest method for a variable workforce because earning tracks contribution. The trade-off is that it needs an accurate record of hours worked to feed it — which is exactly what a time clock produces.
3. Annual lump-sum grant
The full allowance lands at once — typically at the start of the year, an anniversary, or the fiscal year. Instead of drip-feeding, the employee gets the whole bucket up front and draws it down over the period.
Who it suits: organizations that prefer a clean “you get X hours this year” message, and policies where you’d rather not track incremental earning. The thing to decide is what happens to unused hours at year-end — which brings us to the settings.
The knobs that shape any policy
The accrual method is only half the story. Three more settings decide how a policy behaves — as much as the method itself.
- Caps. A maximum balance an employee can hold. Once they hit the cap they stop earning until they take time off, which keeps a generous policy from becoming a runaway liability.
- Carryover. What happens to unused hours at rollover — carry all forward, carry a capped amount, or reset to zero (“use it or lose it”). This is where most PTO disputes start, so decide it explicitly and write it down.
- Waiting period. A delay before a new hire starts earning (or before they can use what they’ve earned). A common way to avoid granting a full allowance to someone in their first few weeks.
- Paid vs. unpaid. Not every leave type draws a balance. Punchwell lets you mark each leave type paid or unpaid; only paid types accrue and draw against a balance, while unpaid types just record the absence.
Because these settings are per leave type, one organization can run a per-hour-worked vacation policy and a monthly-accruing sick policy side by side, each with its own cap and carryover.
How a balance actually gets spent
Earning is only half of it — the balance also has to draw down cleanly, or you’ll never trust the number.
When paid leave is approved in Punchwell, the system draws the hours from the employee’s balance automatically. Every movement — each earn, each draw, and any manual adjustment an admin makes — is written to a running ledger. That means the balance isn’t a mystery figure; it’s the sum of an auditable list of transactions you can trace line by line if someone ever questions it. Employees can see their own balances through self-service, so “how much time do I have left?” stops being a question that lands on HR’s desk every week. That audit trail is the quiet reason accrual beats a shared spreadsheet: when a balance is challenged, you can show exactly how it got there.
Which method should you pick?
A quick rule of thumb:
- Mostly salaried, predictable staff? Monthly accrual is the easiest to explain and administer.
- Hourly or shift workers with variable schedules? Per-hour-worked is the fairest, because earning tracks the hours people actually put in.
- Want a simple “here’s your year’s allowance” message and don’t want to track incremental earning? An annual lump-sum grant, with a clear carryover rule, does the job.
Whichever you choose, set the cap, carryover, and waiting period before you launch, tell your team the rule plainly, and let the tool do the math.
Frequently asked questions
Is accrual measured in days or hours? Almost always hours. Hours divide cleanly across part-timers, overtime, and irregular shifts, so a “day” of PTO is stored as its equivalent in hours and the math runs on hours throughout.
Can I run different accrual rules for vacation and sick leave? Yes. Accrual is set per leave type, so you can run, for example, per-hour-worked vacation alongside monthly-accruing sick leave, each with its own cap and carryover.
What stops a balance from growing forever? A cap. Once an employee reaches the maximum balance, they stop earning until they take time off, which keeps the liability under control.
Where does the balance come from — can employees see it? Every earn, draw, and adjustment is recorded in a ledger, and employees can view their own balance through self-service, so the number is always traceable.
Try it on your own site
PTO accrual feels complicated until you see the three methods laid out — then it’s just a matter of matching the method to how your team works. If you’d like to set it up on a WordPress site you already run, the full feature list shows how leave, accrual, attendance, and payroll export fit together.
Punchwell is a self-hosted WordPress time clock and HR suite by Sturdyhaus, with a built-in PTO accrual engine — monthly, per-hour-worked, or annual grants — plus caps, carryover, and waiting periods, all stored in your own WordPress database.