How to Calculate PTO Accrual: A Step-by-Step Guide

The formula in one line

PTO accrual equals hours worked times your accrual rate, and the annual total is that per-period figure times pay periods a year. In symbols: per period = hours × rate, and per year = per period × periods. That is the whole method — everything else on this page is finding the three inputs honestly and checking the answer backwards. On the worked example, 80 hours worked at a 0.05 accrual rate earn 4.00 hours per period, and over 26 biweekly periods that is 104.00 hours a year.

Step 1: Find your hours worked

Your hours worked are the hours in one pay period, not in a month or a year. The reliable source is your pay stub, which shows the hours for that period. For a full-time biweekly employee that is usually 80 hours, two 40-hour weeks. Be careful about partial periods: a period with a holiday, a sick day or unpaid leave may show fewer hours, and fewer hours mean less accrual that period. If you work variable hours, use a typical period rather than your busiest one, or run the calculation once for a light period and once for a heavy one so you can see the range. The hours figure is also the easiest input to verify, because it is printed on every stub.

Step 2: Find your accrual rate

Your accrual rate is the PTO hours you earn for each hour you work, and it lives in your employer's PTO policy or on your pay stub. A rate of 0.05 means you earn five hundredths of an hour of PTO for every hour worked, which is the same as one hour of PTO for every 20 hours worked. Rates vary by employer, by tenure and sometimes by role, and some employers raise the rate after a set number of years, so a colleague with longer service may accrue faster than you on the same hours. If your policy states accrual in days per year instead of a rate, convert it: divide the annual days by your annual hours, then multiply by 8 for a day in hours. A policy of 13 days a year for a 2,080-hour employee, for example, is 104 hours a year, which is 0.05 per hour worked.

Step 3: Find your pay periods per year

Your pay periods per year are how many paydays fall in a year on your schedule. Biweekly pay, every two weeks, is 26 periods. Weekly pay is 52 periods. Monthly pay is 12 periods, and semimonthly pay, twice a month, is 24. This input is the one people most often get wrong, because biweekly and semimonthly sound alike but give different annual totals: the same 4.00 hours per period is 104.00 hours a year on biweekly pay and 96.00 hours on semimonthly pay. Count your actual paydays over a year, or check your payroll schedule, rather than guessing from the word biweekly alone.

Step 4: Multiply, in order

First multiply hours by rate to get the per-period accrual. Then multiply that by the periods per year to get the annual total. On the example: 80 hours × 0.05 is 4.00 hours per period, and 4.00 × 26 is 104.00 hours a year. Doing it in two steps matters, because it lets you see which input is doing the damage when the answer looks wrong — an annual total that seems too high is usually a period count that is too high, and a per-period figure that seems too low is usually a rate that is lower than you assumed.

Step 5: Check the answer backwards

Work the answer backwards before you accept it. Divide the per-period accrual by the rate to recover the hours: 4.00 ÷ 0.05 is 80 hours, which matches the stub. Divide the per-period accrual by the hours to recover the rate: 4.00 ÷ 80 is 0.05, which matches the policy. And divide the annual total by the per-period accrual to recover the period count: 104.00 ÷ 4.00 is 26, which matches the biweekly schedule. If any of the three recovered figures disagrees with what you typed in, one of your inputs is wrong — find it before you argue about the balance.

Three worked examples

A full-time biweekly employee: 80 hours × 0.05 is 4.00 hours per period, and 4.00 × 26 is 104.00 hours a year, or 13 eight-hour days. This is the headline case, and it is the one most full-time employees should start from.

A part-time employee on the same rate: 40 hours × 0.05 is 2.00 hours per period, and 2.00 × 26 is 52.00 hours a year. The rate is identical, but half the hours mean half the accrual — PTO accrual scales with hours worked, not with headcount.

A higher rate on monthly pay: 160 hours in a monthly period × 0.08 is 12.80 hours per period, and 12.80 × 12 is 153.60 hours a year. The per-period figure looks large because the period is a whole month, but the annual total is what matters for comparison, and it is higher than the headline case because the rate is higher.

Common mistakes

Using monthly hours with biweekly periods. If you multiply a monthly hour figure by 26 periods, you count every month more than twice. Hours and periods must belong to the same schedule: biweekly hours with 26, monthly hours with 12, weekly hours with 52.

Confusing accrual with payout. Accrual is earning hours as you work; payout is cashing banked hours when you leave. A large accrued balance is not a cash figure until a payout policy prices it, and the payout page, not this one, does that arithmetic.

Ignoring the cap. Many policies cap the balance you can hold. Once you hit the cap, further accrual may pause until you take time off, so the earned figure and the usable balance are not the same number. Check the maximum balance in your handbook.

Forgetting the waiting period. Some employers do not start accrual until after a probationary period, or do not let you use accrued time until it has vested. The formula still earns the hours on paper, but the usable balance lags behind.

What if your rate changes?

Rates often rise with tenure, so a single annual figure can hide two different rates. If your rate rises halfway through the year, calculate each half separately and add them: the periods at the old rate plus the periods at the new rate. For example, 13 periods at 4.00 hours is 52.00 hours, and 13 periods at 6.40 hours, the 0.08 rate on 80 hours, is 83.20 hours, for a year total of 135.20 hours. A blended average rate would give the same total only by accident, so split the year at the change date instead of averaging. The same split applies if your hours change mid-year: calculate each schedule separately, then add.

Try your own numbers on the pto-accrual-calculator — it runs the same formula, shows the branches and the reverses, and lets you work any accrual backwards to the hours, rate or periods behind it.