How the shift differential calculator works
Split your week into hours at the base rate and hours that earned the differential. The calculator adds the differential to your straight-time pay, divides by all hours to find the regular rate, and pays half that rate again for each overtime hour. To find how many of your hours fall in a night window, use the shift hours calculator. The concepts are explained in shift differential pay explained.
Shift differential formula
Worked example
$20.00 base, $2.00 night differential, 30 day hours and 15 night hours
- Straight time: 45 × $20.00 = $900.00, plus 15 × $2.00 = $30.00.
- Regular rate: $930.00 ÷ 45 = $20.67.
- Overtime premium: 5 × $20.67 × 0.5 = $51.67.
- Total: $981.67. Using the base rate alone for overtime would pay $50.00.
Differential rates
| Base rate | + $1.00 | + $2.00 | + 10% | + 15% |
|---|---|---|---|---|
| $15.00 | $16.00 | $17.00 | $16.50 | $17.25 |
| $18.00 | $19.00 | $20.00 | $19.80 | $20.70 |
| $20.00 | $21.00 | $22.00 | $22.00 | $23.00 |
| $25.00 | $26.00 | $27.00 | $27.50 | $28.75 |
| $30.00 | $31.00 | $32.00 | $33.00 | $34.50 |
Frequently asked questions
What is a shift differential?
Extra pay for working less desirable hours, such as nights, weekends, or rotating shifts. It is usually a set amount per hour, such as $2, or a percentage of the base rate, such as 10%.
Is a shift differential required by law?
Federal law does not require employers to pay a shift differential. When an employer does pay one, federal rules require it to be included in the regular rate used to calculate overtime.
How does a shift differential affect overtime?
Overtime is based on the regular rate, which is total straight-time earnings, including differentials, divided by total hours. So overtime pays more than 1.5 × the base rate. In the example above, the regular rate rises from $20.00 to $20.67.
How do I calculate a percentage differential?
Multiply the base rate by the percentage. A 10% differential on $20.00 an hour is $2.00, so differential hours pay $22.00.
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How this calculator was built. The formula, defaults, and edge cases are documented in a research record and covered by automated tests. It estimates gross amounts from your inputs; it does not determine legal entitlements, taxes, or take-home pay. Read our methodology and disclaimer.
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