Overtime Pay Calculator for Rotating Shifts

What counts as overtime under federal law

The Fair Labor Standards Act (FLSA) requires covered, non-exempt employees to be paid at least 1.5× their regular rate for every hour worked beyond 40 in a single workweek. A workweek is a fixed, recurring period of 168 consecutive hours — it doesn't have to start on Sunday, but once your employer sets it, it stays fixed. Overtime is calculated workweek by workweek; hours can't be averaged across two weeks to dodge the threshold, even if your pay period is bi-weekly or monthly.

The 7(k) exemption for public safety

Fire protection and law enforcement employees are often scheduled on 24-hour tours that don't map cleanly onto a standard workweek. Section 7(k) of the FLSA lets qualifying employers use a longer "work period" — between 7 and 28 days — with a correspondingly higher hour threshold before overtime applies. For a 28-day period, that threshold is commonly 212 hours for fire protection employees and 171 hours for law enforcement, though exact figures depend on the work period length your employer has adopted. This is why a 24/48 schedule can look "overtime-heavy" under a standard 40-hour calculation but fall within normal hours under 7(k).

Eligibility varies: 7(k) only applies to qualifying public-safety roles, and the exact threshold depends on your employer's declared work period. If you're not sure which rule applies to you, your HR or payroll department can confirm.

Worked example: a 3x12 rotating nurse

Take a nurse on a 3x12 rotating pattern who works three consecutive 12-hour day shifts (Sunday, Monday, Tuesday — 36 scheduled hours), then picks up a 4-hour hold-over at the end of the Tuesday shift. That workweek now totals 40 hours exactly — no overtime yet. If she's called in for one more 12-hour shift later that same Sunday–Saturday workweek, the next 12 hours all fall above the 40-hour line and are paid at 1.5× her base rate. Because the threshold resets at the start of the next workweek, those same hours worked one day later — in a new workweek — would count as regular time instead.

Run your own overtime numbers

Enter your pattern and pay rate to see exactly which hours cross the overtime line.

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Common overtime questions

Is overtime pay taxed at a higher rate?

No. Overtime pay is taxed as ordinary income, at the same marginal rates as your regular wages. It can look like it's withheld more heavily because a bigger paycheck pushes more of that check into a higher withholding bracket for that pay period — but your actual tax rate on the income doesn't change.

Can my employer average my hours across two weeks to avoid paying overtime?

Generally, no. Under federal law each workweek is evaluated on its own — hours over 40 in one workweek can't be offset against a lighter week to avoid overtime, even under a bi-weekly or monthly pay schedule.

Does my employer have to pay overtime for hours worked on a holiday?

Federal law doesn't require extra pay just because a shift falls on a holiday — only actual hours over the workweek threshold trigger overtime. Holiday premium pay is a matter of company policy or union contract, not federal law, which is why ShiftRosterPay lets you mark holiday shifts manually.

Does this calculator account for state-specific daily overtime rules?

Not by default. This calculator models the federal FLSA baseline (40 hours/workweek, or the 7(k) exemption for qualifying public-safety roles). A handful of states apply additional daily overtime thresholds; check your state labor department if that might apply to your job.