📈 PTO Accrual Calculator

Last updated: June 11, 2026

📈 PTO Accrual Calculator

Project your paid time off balance to any future date based on your pay schedule and annual allowance.

Measure PTO in:

Your PTO Projection

—
Accrued Per Period
—
Pay Periods
—
Total Accrued
—
Projected Balance

Breakdown

Starting Balance—
Accrual Rate—
Pay Periods Until Target—
Total Accrued—
Planned PTO Used—
Projected Balance on Target Date —

How to Calculate PTO Accrual and Project Your Balance to Any Future Date

Knowing exactly how much paid time off you have — and how much you will have three months from now — changes the way you plan your life. Booking a vacation, scheduling surgery, or simply taking a long weekend without anxiety requires one thing: an accurate picture of your PTO balance on a specific future date. This guide walks you through the mechanics of PTO accrual from the ground up, so you understand not just the number but where it comes from.

What "Accrual" Actually Means

Many employers do not dump your full PTO allowance into your account on January 1. Instead, they credit it gradually as you work — a model called accrual. You earn a fraction of your annual entitlement each pay period. If your company gives you 15 days a year and pays you biweekly, you earn roughly 0.577 days every two weeks. By the end of the year those small installments add up to your full 15 days, but mid-year you only have access to what you have earned so far.

This matters for planning. If you want to take a week off in August, you need to know whether your balance will be large enough by then — not just whether your annual allowance covers it on paper.

The Four Pay Period Frequencies and How They Change the Math

Your accrual rate depends entirely on how often your employer runs payroll. There are four common structures:

  • Weekly (52 pay periods/year): You earn annual PTO ÷ 52 per paycheck. For 15 days annual PTO, that is 0.288 days per week. Small per-period amounts, but they compound quickly.
  • Biweekly (26 pay periods/year): The most common US structure. Annual PTO ÷ 26. For 15 days, you earn 0.577 days every two weeks.
  • Semi-monthly (24 pay periods/year): Paid on two fixed dates each month, typically the 1st and 15th or 1st and 16th. Annual PTO ÷ 24. For 15 days, that is 0.625 days per half-month.
  • Monthly (12 pay periods/year): Least common. Annual PTO ÷ 12. For 15 days, you earn 1.25 days each month. Largest single credit, but you wait the longest between accruals.

A subtle point: semi-monthly is not the same as biweekly even though both result in 24 or 26 payments. Biweekly means every 14 calendar days. Semi-monthly means twice per calendar month. Over a year the difference is small (two extra biweekly paychecks annually), but when projecting to a specific date, the counting method differs and can shift your result by one full period.

Step-by-Step: Projecting Your PTO Balance

Here is the exact process the calculator above uses, which you can also do on paper.

Step 1 — Find your accrual rate per period. Divide your annual PTO entitlement by the number of pay periods per year. If you receive 120 hours (15 days × 8 hours) annually on a biweekly schedule: 120 ÷ 26 = 4.615 hours per period.

Step 2 — Count complete pay periods between your start date and target date. For weekly and biweekly schedules, divide the number of calendar days in the range by 7 or 14 and take the whole number (floor). For monthly schedules, count full calendar months. For semi-monthly, count half-months by tracking how many 1st-and-16th boundaries the date range crosses. Always use complete periods — a day into a new period does not earn you that period's credit until the pay run closes.

Step 3 — Multiply and add. Accrued amount = accrual rate × number of periods. Projected balance = current balance + accrued amount − any planned PTO use.

Example: You have 4 days in your bank today (June 24). Your company gives 15 days per year on a biweekly schedule. You want to take 5 days off in late October and need to know your balance on November 1.

  • Days between June 24 and November 1 = 130 days
  • Complete biweekly periods = floor(130 ÷ 14) = 9
  • Accrual rate = 15 ÷ 26 = 0.577 days per period
  • Total accrued = 0.577 × 9 = 5.19 days
  • Projected balance = 4 + 5.19 − 5 = 4.19 days remaining after the trip

That 4.19-day cushion gives you confidence to book the vacation. Without this calculation, you might have assumed your balance was too tight.

The Difference Between Hours and Days — and Why It Matters

Some HR systems track PTO in hours, others in days. If your company uses hours, multiply days by your standard workday length (usually 8 hours). A 15-day annual allowance = 120 hours. The math is identical — just make sure you apply the same unit consistently. Using the wrong unit inflates your projected balance by a factor of 8, which leads to very painful surprises when you actually try to submit a time-off request.

When using the calculator on this page, pick your unit at the top (Days or Hours) and stick to it across all inputs.

Accrual Caps, Use-It-or-Lose-It Policies, and Other Gotchas

The projection above assumes your employer lets your balance grow without limit. Many do not.

Accrual caps: Once your balance hits a ceiling (often 1.5× your annual allowance), accrual stops until you draw it down. If you are approaching your cap, actual growth will be less than the formula predicts.

Use-it-or-lose-it / "forfeiture" policies: Some states permit employers to require employees to use PTO before a reset date (typically December 31 or your work anniversary). If you are subject to this rule, any unused balance above the carryover limit disappears, making your December 31 projection essentially zero regardless of what you have earned.

Waiting periods: New employees sometimes cannot use accrued PTO for a probationary period — 30, 60, or 90 days. The balance accrues during this time, but the PTO cannot be taken. Know whether you are still in this window.

Anniversary vs. calendar-year accrual: If your PTO year resets on your hire anniversary rather than January 1, adjust your "start date" input to that anniversary date for the most accurate projection.

How to Use the PTO Projection for Smarter Vacation Planning

Run the calculator for each vacation you are considering in the next 12 months and treat them sequentially. First project to your earliest planned trip, note the balance, then use that projected balance as the "current balance" for the next trip's calculation. This chained approach accounts for multiple uses in a single year without double-counting.

Also factor in any mandatory PTO your employer requires — some companies force employees to take PTO during holiday shutdowns. Subtract those days from your available balance the same way you would subtract a planned vacation.

Finally, check your paystub or HR portal for the exact accrual rate printed there, and compare it against the formula above. Small differences sometimes appear due to rounding rules in payroll software. The paystub figure is always authoritative — use it over a hand-calculated rate if you see a discrepancy.

FAQ

What is the difference between biweekly and semi-monthly pay for PTO accrual?
Biweekly means you are paid every 14 calendar days, resulting in 26 pay periods per year. Semi-monthly means you are paid on two fixed dates each month (such as the 1st and 15th), resulting in 24 pay periods per year. Because biweekly gives you two extra pay periods annually, your per-period accrual rate is slightly lower, but you accrue more frequently. Over a full year the total PTO earned is identical — the difference only appears when projecting to a specific mid-year date.
Does PTO accrue during paid holidays or while I am already on PTO?
In most US employer plans, PTO continues to accrue during paid company holidays and while you are using PTO, since you are still technically an active employee in the pay period. However, some employers pause accrual during unpaid leave (such as an extended medical leave beyond your balance). Check your employee handbook or HR policy document for the specific rule at your company.
How do accrual caps affect my projected balance?
An accrual cap sets a maximum balance you can hold. Once you reach that ceiling, new PTO stops accruing until you use some. If the calculator projects a balance higher than your company's cap, your real balance will stop at the cap. To account for this, note your company's cap and treat any projected amount above it as not actually accessible until you draw down your balance first.
Can I project PTO in hours instead of days?
Yes. Toggle the calculator to Hours mode and enter your annual PTO allowance in hours (a common value is 120 hours for a 15-day policy with 8-hour workdays). Enter your current balance and planned usage in hours as well. The math is identical — only the unit changes. Using hours is more precise if your employer's payroll system tracks fractions of an hour, which is common in hourly-worker and healthcare environments.
What if my company resets PTO on my hire anniversary instead of January 1?
Set the Start Date field to your most recent hire anniversary date. The calculator will then count pay periods from that anniversary forward, giving you an accurate projection within your current PTO year. If your target date crosses your next anniversary, be aware that your balance may reset or that unused days may be forfeited depending on your employer's carryover policy.
Why does the calculator use complete pay periods instead of counting partial ones?
PTO accrual is credited at the end of each complete pay period, not on a daily basis. Until a pay run closes, you have not earned that period's credit. Using partial periods would overstate your available balance, potentially causing you to request time off that has not technically been credited yet. The calculator intentionally takes the floor (whole number) of pay periods to reflect what would actually appear in your HR system on any given date.