Shift Differential Calculator

Shift pay rate = base rate + differential (a percent of base, or a flat $/hr add-on).

Straight-time pay = (base rate × regular hours) + (shift pay rate × differential hours).

Blended regular rate = straight-time pay ÷ straight-time hours — the weighted average of all straight-time pay.

Overtime pay = overtime hours × 1.5 × blended regular rate — not 1.5 × base rate.

Total gross pay = straight-time pay + overtime pay.

• Calculate the shift pay rate by adding the differential to the base rate.
• Multiply each group of hours (regular, differential) by its rate and add them together for straight-time pay.
• Divide straight-time pay by straight-time hours to get the blended regular rate.
• Pay overtime hours at 1.5 times that blended rate, not 1.5 times the plain base rate.
• Add straight-time pay and overtime pay for total gross pay.

Total gross combines base and premium hours, and the blended rate is total straight-time pay divided by straight-time hours — the rate overtime should be built on when a premium applies.

Common mistakes and assumptions

• Calculating overtime on the base wage alone when premium hours were worked; overtime uses the blended regular rate.
• Entering the premium as a total rate rather than the differential on top of base, or the reverse — check the unit on the field.
• Counting the same hours in both base and premium buckets.

A $20/hr base rate, 32 regular hours, 8 hours on a 10% night differential, and 5 hours of overtime.

1. 1Differential rate = $20 × 10% = $2.00/hr, so the shift pay rate = $22.00/hr.
2. 2Regular-hours pay = $20 × 32 = $640. Differential-hours pay = $22 × 8 = $176.
3. 3Straight-time hours = 32 + 8 = 40, straight-time pay = $640 + $176 = $816.
4. 4Blended regular rate = $816 ÷ 40 = $20.40/hr.
5. 5Overtime pay = 5 × 1.5 × $20.40 = $153.00.
6. 6Total gross pay = $816 + $153 = $969.00, and the differential premium is $2.00 × 8 = $16.00.

Why isn't overtime just 1.5× my base rate?

Federal wage law generally requires overtime to be based on the 'regular rate of pay,' which includes shift differentials and most non-discretionary pay, not just the base hourly rate. Using only the base rate underpays overtime whenever a differential applies.

How is the blended rate calculated?

Add up all straight-time earnings for the week (regular hours plus differential hours at their respective rates) and divide by total straight-time hours worked. That weighted average becomes the base for the overtime multiplier.

What's a typical shift differential amount?

Common ranges are 5–15% of base pay for evening or night shifts, and sometimes higher (or a flat $1–$5/hr) for weekends, holidays, or hazardous conditions. It varies widely by employer and industry.

Does this apply to salaried employees?

This calculator is built for hourly pay. Salaried non-exempt employees who work shift differentials also need their regular rate recalculated for overtime, but the math for converting a salary into an hourly equivalent first is different.

What if I have more than one differential rate in a week?

Run each block of hours through as a separate 'differential hours' group by calculating them individually, then combine the straight-time pay and hours manually before dividing for the blended rate — the underlying formula is the same no matter how many rates you mix.

Is the differential premium the same as differential pay?

No. Differential pay is the full pay for those hours (base + extra), while the differential premium is only the extra amount above what those hours would have earned at the base rate.