Is a shift differential required by law?

No — federal law doesn't require one. It's up to the employer or the union contract. But once it's paid, it counts toward the regular rate for overtime.

What's a typical differential?

Often 5–15% of base pay, or a flat $1–$3 an hour, with nights usually paying more than evenings.

What if hours change between weeks?

Figure each workweek on its own — overtime can't be averaged across weeks.

Work & Pay

Shift Differential Calculator

Pay for a week split across day, evening, and night shifts — with the differentials, and overtime figured on the blended regular rate the way federal law requires.

Ben / Reviewed Sep 27, 2026 / v2.0.0

Results

Showing the numbers you calculated

Heads up

The shift differentials count toward the regular rate, so overtime pays $6.00 more than figuring it on the base rate alone would.

Pay for the week: $1,118.00; $23.29 an hour on average
Regular rate: $21.50; All straight-time pay ÷ all hours
Differential pay: $72.00
Overtime premium: $86.00; 8 hours over 40
Per year at this pace: $58,136.00

By shift

Straight time for every hour. Overtime is added on top.

Swipe the table sideways to see all 6 columns.

By shift
Shift	Hours	Rate	Base pay	Differential	Pay
Day shift	8.00	$20.00	$160.00	$0.00	$160.00
Evening shift	16.00	$21.50	$320.00	$24.00	$344.00
Night shift	24.00	$22.00	$480.00	$48.00	$528.00

What this does

Evening and night shifts often pay extra — a shift differential. That extra has to be included when overtime is figured, and it's one of the most common payroll mistakes when it isn't.

This adds up a week across shifts, then figures overtime on the blended rate the law requires (or on the shift's own rate, if that's your agreement).

How the math works

shift rate = base rate + differential
straight time = Σ hours on each shift × that shift's rate

The regular rate is the average across every hour:

regular rate = straight time ÷ total hours
overtime premium = 0.5 × regular rate × hours over 40

Straight time already paid every hour once. The overtime premium is the extra half — so the total is the same as paying 1.5× the blended rate for the overtime hours.

Check my math: a worked example

$20.00 base, 8 day, 16 evening, and 24 night hours this week.

Rates: day $20.00, evening $21.50, night $22.00.
Straight time for all 48 hours: $1,032.00 (including $72.00 of differentials).
Regular rate: $1,032.00 ÷ 48 = $21.50. Overtime premium on 8 hours: $86.00 (it'd be $80.00 if the differentials were wrongly left out).
Total for the week: $1,118.00.

These numbers come straight from the calculator using its example inputs — if the math ever changes, this example changes with it.

Mistakes I see a lot

Figuring overtime on the base rate and ignoring the differential.
Only counting overtime on the night shift. Overtime is hours over 40 in the week, whichever shift they're on.
Using the shift-rate method without an advance agreement.

Questions people ask

Is a shift differential required by law?: No — federal law doesn't require one. It's up to the employer or the union contract. But once it's paid, it counts toward the regular rate for overtime.
What's a typical differential?: Often 5–15% of base pay, or a flat $1–$3 an hour, with nights usually paying more than evenings.
What if hours change between weeks?: Figure each workweek on its own — overtime can't be averaged across weeks.

Assumptions and limits

One workweek under the FLSA: overtime is due for hours over 40, on any shift.
Shift differentials are part of the regular rate. With the weighted method (29 CFR 778.115), the regular rate = all straight-time pay ÷ all hours, and each overtime hour earns half of that on top.
The shift-rate method (29 CFR 778.419) pays overtime at 1.5× the rate of the shift the overtime hours were worked on — allowed only if agreed in advance.
A percentage differential is a percent of the base rate, rounded to the cent per hour.
No daily overtime or state rules. The yearly figure assumes every week looks like this one.

Ben’s notes on this

Related calculators

Overtime Pay
Overtime pay for one workweek, figured the way the FLSA requires — including how a bonus raises the regular rate, which most people (and some payroll systems) get wrong.
Salary to Hourly
Turn a salary into an hourly rate (or the other way around) — plus what you really make per hour worked once time off and overtime are counted, and what each paycheck comes to.
Employee True Cost
What an employee really costs you: pay, employer payroll taxes (with the real wage bases), benefits, and overhead — per year, per month, and per productive hour, plus the extra first-year hiring costs.
Retroactive Pay
Back pay when a raise or a pay correction reaches back to earlier paychecks — hourly or salaried, overtime included, with a rough take-home estimate and the journal entry.

Spot an error?

This is a public notebook and I do make mistakes. If a number looks off, tell me — I fix things and note the change in the changelog.

Disclaimer: Educational and planning use only. Results depend on what you enter and may not match your lender, your tax return, or professional accounting treatment. Informational content + opinions only — not tax/legal advice.

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