Biweekly means every two weeks
A biweekly schedule normally creates 26 pay periods in a 52-week year. Because calendar years do not divide perfectly into two-week blocks, some payroll calendars require careful date handling.
Semi-monthly means twice per month
A semi-monthly schedule normally creates 24 pay periods per year, often around the middle and end of each month. The number of workdays inside each period can vary.
Why paycheck amounts differ
For the same annual salary, dividing by 26 produces a smaller regular gross check than dividing by 24. The annual total can still be the same. Hourly workers may see larger variation because actual workdays differ between periods.
Use the correct annualization factor
Do not multiply a biweekly amount by 24 or a semi-monthly amount by 26. Label the schedule clearly in budgets, offers and payroll exports.