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Semi-monthly · split workweeks

Semi-Monthly Overtime Calculator

Semi-monthly pay splits workweeks across paychecks. This calculator keeps overtime correct by computing it per workweek, not per pay date.

Calculation breakdown

Pay frequency comparison

SchedulePaychecks/yrAligns with workweeks?
Weekly52Yes — 1 week per check
Biweekly26Yes — 2 weeks per check
Semi-monthly24No — splits workweeks
Monthly12No — splits workweeks

How to use this calculator

  1. 1

    Identify each workweek

    Semi-monthly periods (13–16 days) rarely line up with workweeks. Break your time into fixed 7-day workweeks first.

  2. 2

    Enter each workweek's hours

    Put each week's total in its own box (use Week 1 and Week 2 for the two weeks touching this paycheck).

  3. 3

    Apply overtime per week

    Overtime is calculated for each workweek separately, then the pay is combined — never averaged across the pay period.

The takeaway for semi-monthly workers: don't let a paycheck date hide overtime. If a heavy week is split between two checks, the overtime still belongs to that week. Compare your stubs against a per-week calculation, and see the payroll schedules guide for the full picture.

Frequently asked questions

How is overtime handled on semi-monthly pay?
Overtime is computed per workweek, not per pay period. Because semi-monthly periods split workweeks, a week that straddles two paychecks has its overtime calculated across the full week and trued-up on the paycheck that contains the end of that week.
What is the difference between semi-monthly and biweekly?
Semi-monthly is twice a month (24 paychecks/year) on fixed dates like the 1st and 15th, with periods of 13–16 days. Biweekly is every 14 days (26 paychecks/year). Biweekly aligns neatly with workweeks; semi-monthly splits them, which complicates overtime.
How many hours is a semi-monthly pay period?
A full-time semi-monthly period averages about 86.67 hours (2,080 annual hours ÷ 24 periods), but the actual days vary from 13 to 16, so worked hours differ each period.
Why is semi-monthly hard for hourly workers?
Because pay periods don't match workweeks, payroll must track overtime by workweek and reconcile partial weeks across two checks. This is why most hourly employers prefer weekly or biweekly pay.
Can overtime be delayed to the next paycheck?
Overtime should be paid on the regular payday for the period in which the workweek ends. A week split across two semi-monthly checks is completed (and its overtime paid) on the second check.

Sources & further reading

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