How to Calculate PTO: Formulas & Examples

PTO accrual comes down to one idea: decide how much time off an employee earns in a year, then spread that amount across the time they work. There are three common ways to do the spreading, annual, per-pay-period, and per-hour-worked, and each fits a different kind of workforce. Below are the exact formulas with worked numbers you can copy.

Start by converting everything to hours

Before any formula works, pick a single unit. Use hours. Days seem simpler, but they fall apart the moment someone works a 6-hour shift, takes a half day, or works part-time. Hours never have that problem.

To convert a policy stated in weeks or days into hours, multiply by the employee's normal schedule:

• Two weeks for a 40-hour employee equals 40 times 2, which is 80 hours.
• 15 days for an 8-hour-per-day employee equals 15 times 8, which is 120 hours.
• Two weeks for a 30-hour part-timer equals 30 times 2, which is 60 hours.

Notice the part-timer earns fewer hours for the same "two weeks." That is correct and intentional, the formulas below preserve that fairness automatically.

Method 1: Annual (lump sum or front-loaded)

The simplest method. The employee receives their full annual allotment at one point in time, usually January 1 or their work anniversary. No running math required during the year.

Formula:

Annual PTO hours equals weeks of PTO times weekly hours.

Worked example: A full-time employee gets three weeks of PTO and works 40 hours a week.

3 times 40 equals 120 hours, granted all at once on January 1.

This is easy to administer but has a catch: if an employee quits in February having used most of a balance they had not really "earned" yet, you may have overpaid time off. Many businesses front-load anyway because the simplicity is worth it, and most people do not game it. If that risk worries you, use one of the accrual methods below, which only credit time as it is earned.

Method 2: Per pay period

The most popular method for salaried and full-time staff. The annual allotment is divided evenly across every paycheck, so the balance grows a little each pay period.

Formula:

Accrual per period equals annual PTO hours divided by number of pay periods per year.

The number of pay periods depends on your payroll schedule:

Worked example: An employee earns 80 hours of PTO per year and is paid biweekly.

80 divided by 26 equals 3.0769 hours per pay period. Round display to 3.08 hours, but keep the full decimal in your records so it adds up correctly over the year.

To find the balance at any point, multiply by periods worked:

• After 6 pay periods: 3.0769 times 6 equals 18.46 hours.
• After 13 pay periods (roughly mid-year): 3.0769 times 13 equals 40 hours, exactly half the annual amount, which is the sanity check you want.
• After 26 pay periods (full year): 3.0769 times 26 equals 80 hours.

Watch the rounding

If you round each period's accrual up to 3.08 and then multiply by 26, you get 80.08 hours, eight extra minutes of PTO per employee per year. Tiny, but across 50 employees it adds up, and it makes balances look "off" by a hair. The fix is to store the precise decimal and only round for display. Software that tracks accruals to several decimal places, like the PTO accrual calculator, avoids this entirely.

Method 3: Per hour worked

The fairest method for hourly, part-time, and variable-schedule employees. PTO accrues based on hours actually worked, so someone who picks up extra shifts earns more, and someone who works less earns proportionally less.

Formula:

Accrual rate per hour equals annual PTO hours divided by expected annual work hours.

A standard full-time year is 2,080 hours (40 hours times 52 weeks).

Worked example: A full-time employee earning 80 hours of PTO a year.

80 divided by 2,080 equals 0.0385 hours of PTO per hour worked.

Now apply it to real hours:

• Works 80 hours in a biweekly period: 80 times 0.0385 equals 3.08 hours accrued, the same as the per-period method, as expected.
• Works 2,080 hours in a year: 2,080 times 0.0385 equals 80 hours, the full allotment.

Where it shines, part-timers: A part-time employee works about 1,040 hours a year (20 hours a week). Using the same 0.0385 rate, they accrue 1,040 times 0.0385 equals 40 hours of PTO, exactly half of the full-time benefit, scaled to the hours they actually worked. No special policy needed.

Some states require PTO or sick-leave accrual at a fixed rate such as one hour for every 30 hours worked. To check whether your rate clears that floor, divide: 1 divided by 30 equals 0.0333. Since 0.0385 is larger than 0.0333, the example policy above is more generous than the legal minimum. If you need to count actual on-the-clock days for a custom year, the working days calculator handles holidays and weekends for you.

A side-by-side comparison

Here is the same 80-hour annual benefit expressed three ways for a full-time employee:

All three deliver 80 hours over a full year. The difference is timing and fairness: annual is simplest, per-period is steady and predictable, and per-hour is the most accurate for anyone whose hours vary.

Tiered accrual by tenure

Most policies increase PTO with years of service. The math does not change, you just recalculate the rate whenever the annual allotment changes.

Example tiers:

1. Years 1 to 2: 80 hours per year, which is 3.08 hours biweekly.
2. Years 3 to 5: 120 hours per year, which is 4.62 hours biweekly.
3. Years 6 and up: 160 hours per year, which is 6.15 hours biweekly.

The tricky part is the changeover. If someone hits their third anniversary mid-year, decide in advance whether the new rate starts on the anniversary date or the next January 1. Either is fine, but write it down so it is applied the same way every time and document it in a clear PTO policy.

Handling caps and carryover

Two settings sit on top of accrual and quietly change the numbers.

Accrual cap (maximum balance). Once an employee hits the cap, accrual pauses until they use some time. If the cap is 120 hours and a worker is at 120, the next paycheck adds zero hours, not the usual 3.08. They start earning again only after dropping below the cap. This prevents balances from ballooning.

Annual carryover limit. This controls how much rolls into the new year. With a 40-hour carryover limit, an employee ending December with 56 hours starts January with 40 hours, and the other 16 are forfeited (in "use-it-or-lose-it" states this must be allowed by law, so check your state rules). A true accrual cap and a carryover limit are different levers, you can use one, both, or neither.

What PTO actually costs you

Accrued PTO is a real liability. When an employee has 60 hours of unused PTO, you owe them that time, and in many states you must pay it out in cash when they leave.

Quick cost example: An employee earning 30 dollars an hour with 60 hours of accrued PTO represents 30 times 60 equals 1,800 dollars of liability sitting on your books. Multiply across your team and the number gets real. To model this for your whole staff, run the figures through the PTO cost calculator.

A repeatable checklist

To calculate any employee's PTO accrual, work through these steps:

1. Set the annual hours. Convert weeks or days into hours using the employee's actual weekly schedule.
2. Choose a method. Annual for simplicity, per-period for salaried staff, per-hour for hourly and part-time staff.
3. Compute the rate. Divide annual hours by 26, by 24, or by 2,080, depending on the method.
4. Keep full decimals. Store at least four decimal places and round only for display.
5. Apply caps and carryover at the end of each period and each year.
6. Track the running balance. Accrued minus used equals available.

Do these by hand for one employee and the logic is clear. Do them for twenty employees across different schedules, tenures, and caps, every pay period, and a spreadsheet starts dropping decimals and breaking formulas.

That is exactly what SimplyPTO automates: set the rate once, and balances accrue, cap, and carry over correctly for every employee without manual math. Start a free trial and let the calculations run themselves.