How PTO accrual works — and how to calculate it
Paid time off (PTO) accrual is the process by which employees earn vacation, sick, or personal days over time. Employers use three primary models — per pay period, per hour worked, and lump sum — each with different implications for payroll accounting, employee scheduling, and legal compliance under the FLSA and state labor laws.
Per pay period accrual is the most common method for salaried employees. An employee earning 15 days annually on a bi-weekly schedule (26 pay periods) accrues 0.5769 days per period. After the 14th pay period they have accumulated 8.08 days. This method aligns PTO earning directly with payroll processing, making it easy to reflect in any payroll system. For semi-monthly payroll (24 periods), the same 15 days becomes 0.625 days per period.
Per hour worked accrual is standard for hourly and part-time employees. A common benchmark is 0.04 hours of PTO per hour worked, which gives a full-time employee (2,080 hrs/year) about 83.2 hours (10.4 days) annually. Several states now mandate minimum sick leave via hourly accrual — Arizona requires 1 hour per 30 hours worked; Michigan 1 per 35; Illinois 1 per 40. See the Overtime Pay Calculator for additional FLSA hour tracking.
Lump sum PTO deposits the full annual balance on January 1 or the employee's anniversary date. It simplifies recordkeeping but creates a larger liability at year-start. If your employer uses a "use-it-or-lose-it" policy, check your state's rules — California treats accrued PTO as earned wages and prohibits any forfeiture policy. Colorado, Nebraska, and North Dakota have similar wage-parity protections.
Cash value of PTO is calculated as: balance days × (hourly rate × 8 hours/day). For example, 10 days of unused PTO at $25/hr is worth $2,000. When paid out, this amount is treated as supplemental wages subject to 22% federal withholding plus FICA. See our Payroll Tax Calculator or Employer Tax Calculator for exact withholding on payout amounts.