Shift differential calculator. Federal FLSA on the blended rate.
- Tool
- Live
- Reviewed
- 2026.05.04
- Privacy
- Browser-only
Methodology
The math, in plain English.
Under the federal Fair Labor Standards Act, non-exempt employees earn overtime when weekly hours exceed 40. The overtime premium is half the regular rate, applied to hours above 40, on top of straight-time pay for all hours worked.
The wrinkle that trips up most paycheck reviews is that shift differentials are part of the regular rate, not an add-on. So if you work 48 hours at $40 base with a $5 night differential on 36 of those hours, your regular rate isn’t $40. It’s ($40 × 48 + $5 × 36) ÷ 48 = $43.75/hr. Your OT premium is half of that, not half of $40.
That’s the formula this tool uses. State-specific rules (California daily overtime, double time, seventh-consecutive-day premiums) and contract-specific blended rates aren’t modeled. Anything that comes out of your paycheck after gross (taxes, retirement, premiums, dues) also isn’t modeled.
If you suspect your employer is calculating overtime on the base rate instead of the blended rate, that’s a known FLSA issue and worth checking with HR or your union rep. The Department of Labor has Fact Sheet #56A covering the regular rate calculation in detail.
Common questions
- How is overtime calculated here?
- The federal Fair Labor Standards Act way: shift differentials are part of the regular rate, so overtime above 40 hours per workweek is paid at half the blended (base + differentials) rate, on top of straight-time pay for those hours. This is the legal default for non-exempt EMS and nursing payroll in the US.
- Does this handle California daily overtime?
- No. California's daily overtime rules (1.5x after 8 hours per day, 2x after 12, seventh-consecutive-day rules) are not modeled in v1. If you work in a state with daily overtime, the weekly gross shown here will understate what you're actually owed once daily thresholds are hit.
- Why does my paystub differ from this number?
- This calculator returns gross weekly pay before taxes, retirement, health premiums, union dues, and any pre-tax deductions. Your paystub also reflects employer-specific blended rates, shift premiums tied to specific hours of the day, and contract-specific bonuses that this tool does not model.
- Where does my data go?
- Nowhere. This calculator runs entirely in your browser. No inputs are sent to a server, stored in cookies, or logged. Closing the tab clears everything.