PAYROLL GLOSSARY
Semi-Monthly Pay
Definition: Semi-monthly pay means you are paid twice per month, usually for 24 paychecks per year.
Employers often schedule semi-monthly payroll on fixed calendar dates such as the 15th and the last day of the month. That makes it different from biweekly payroll, which runs every 14 days and usually produces 26 paychecks per year. The gross salary can be the same under either system, but each paycheck is divided differently because the number of pay periods changes.
The IRS treats payroll period as an input to withholding. Publication 15-T includes separate tables for weekly, biweekly, semi-monthly, monthly, and daily payroll periods because federal income tax withholding is annualized and then converted back to the current check. In practice, that means a worker can see a slightly different withholding amount on a semi-monthly schedule than on a biweekly schedule even when annual salary is unchanged.
If you are comparing an offer, reviewing a raise, or checking a pay stub, always confirm the pay frequency before comparing paycheck amounts. The fastest next step is to run the same salary through a semi-monthly and biweekly calculator using the same filing status and W-4 assumptions.