How 12-hour shift pay is calculated
This calculator converts an hourly wage into weekly, monthly, and annual gross pay for a 12-hour shift schedule — the pattern common in nursing, manufacturing, emergency services, and security. The arithmetic starts from one fact: weekly hours = shifts per week × 12. Hours up to 40 are paid at your effective rate, and hours beyond 40 are paid at the overtime multiplier — 1.5× under the federal Fair Labor Standards Act (FLSA) standard.
The formula
- Effective rate = base hourly rate + shift differential (the differential counts toward the FLSA "regular rate," so overtime is computed on the combined figure).
- Regular hours = min(shifts × 12, 40); overtime hours = max(0, shifts × 12 − 40).
- Weekly gross = regular hours × effective rate + overtime hours × effective rate × 1.5.
- Annual gross = weekly gross × paid weeks per year (52 if you are paid year-round); monthly gross = annual ÷ 12.
Why the shift count matters so much
Because each shift is 12 hours long, a single extra shift swings the week dramatically. Three shifts is 36 hours — below the 40-hour threshold, so no overtime at all. Four shifts is 48 hours, which includes 8 overtime hours at time-and-a-half, so the fourth shift pays more per hour than the first three. Rotations like the 2-2-3 (Panama) schedule alternate between 3-shift and 4-shift weeks, so pay alternates too, even though the average is 3.5 shifts per week.
Interpreting the output
All figures are gross pay — before income tax, Social Security and Medicare, retirement contributions, and insurance premiums. State rules can also differ from the federal weekly standard: California, for example, requires daily overtime after 8 hours (and double time after 12) unless a valid alternative workweek schedule is in place, and hospitals may use the FLSA "8 and 80" system with daily overtime after 8 hours. This tool models the federal weekly-overtime rule only, so check your state law or union contract if those apply.