Shift differential calculator

How the week is priced

Every hour worked is paid first, at whichever rate applied to it. The overtime premium is added afterwards, on top of a rate that already contains the differential.

The division that decides everything. $1,324.80 of straight-time pay divided by 48 hours worked is $27.60 an hour.

That division is the regulation, not a convention. 29 CFR 778.109 defines the regular hourly rate as total remuneration for employment (except statutory exclusions) in any workweek divided by the total number of hours actually worked by him in that workweek for which such compensation was paid. A differential shift creates a second rate inside one workweek, and 29 CFR 778.115 handles that case directly. Where an employee works at two or more different nonovertime rates in a single workweek, his regular rate for that week is the weighted average of such rates. Weighted average is what the division above is. The night hours pull the rate up because there are more of them.

The premium is half the regular rate, not one and a half times it, and that trips up people who are otherwise doing this correctly. The straight-time half of those overtime hours is already sitting in the straight-time earnings line, because every hour worked was paid once at its own rate. Only the extra half is still outstanding. Adding a full one and a half on top of straight-time earnings pays the first 40 hours worth of straight time twice. The two errors point in opposite directions and they do not cancel.

What a base rate calculator leaves out

The same week, run the way the tools on this search result run it, with overtime at one and a half times the base rate.

The base rate run is the layout every tool on this search result uses. Pay 40 hours at the base rate of $24.00, add the differential as a flat $4.80 an hour on the 36 night hours, then pay 8 overtime hours at $36.00. It totals $1,420.80.

The overtime rate on this week is $41.40 an hour once the differential is inside the regular rate, against $36.00 on the base rate. The week's shortfall is smaller than that $5.40 rate gap, because the night hours were still paid their differential straight time either way. What goes missing is the premium half on each overtime hour, $1.80 an hour here, which comes to $14.40 for the week and $748.80 over 52 weeks of the same schedule.

29 CFR 778.207 is the paragraph that settles it, and it names this pay by name. Paragraph (b) says the Act requires the inclusion in the regular rate of such extra premiums as nightshift differentials (whether they take the form of a percent of the base rate or an addition of so many cents per hour) and premiums paid for hazardous, arduous or dirty work. Both forms, in the text, which is why the calculator above takes both. Paragraph (a) closes the other door. When such premiums are paid, they must be included in the employee's regular rate before statutory overtime compensation is computed; no part of such premiums may be credited toward statutory overtime pay. An employer cannot point at the differential already paid and call it the overtime money.

Blended rate by differential size

Same base rate of $24.00, same 12 base hours and 36 differential hours. Only the differential moves.

Weekly gap is what base rate overtime misses on 8 overtime hours. The percent form and the dollar form give the same answer when they land on the same shift rate, which is the point of the first column.

When a shift premium stays out of the regular rate

Not every premium in a pay packet belongs in the regular rate, and flattening that would be wrong. 29 CFR 778.207(a) draws the line between two things that look alike on a pay stub. Extra compensation that qualifies as a statutory overtime premium can be excluded from the regular rate and credited toward the overtime owed. Everything else cannot. A flat differential paid for working nights, weekends inside a normal schedule, or a dirty or hazardous job is in the second group, and paragraph (b) puts nightshift differentials there in writing.

A premium that is genuinely paid as an overtime rate, for hours past a daily or weekly standard set by agreement, is handled under different sections of the same part and is not what this page models. If your differential is structured that way, or your union contract defines the regular rate for you, or your state runs a daily overtime rule that federal law does not, the answer here will not be the whole answer. State law can require more than the federal floor and never less. Use this page for the federal weekly arithmetic and read your agreement for the rest.

Common questions

What this leaves out

Every figure on this page is gross pay, before any withholding. It is an estimate, not tax advice and not legal advice. It excludes federal income tax, Social Security, Medicare, state and local income tax, pre-tax deductions such as a 401(k) or an HSA, and any credit you may claim. For take-home on the same week, run the gross through the paycheck calculator.

It also excludes bonuses, commissions, on-call pay, tips and any other remuneration that would enter the regular rate alongside the differential, and it excludes the statutory exclusions that would come back out. It applies the federal weekly overtime threshold with no daily rule, no seventh day rule, and no alternative workweek. It assumes both rates are at or above the applicable minimum wage, which is the condition 29 CFR 778.115 attaches to the weighted average, and it assumes the employee is non-exempt.

Sources

The regulation text this page computes from, linked in full.

• 29 CFR 778.109, the regular rate is an hourly rate. Total remuneration divided by hours actually worked. This is the division in the card above.
• 29 CFR 778.115, employees working at two or more rates. The weighted average rule, which is what a differential shift creates.
• 29 CFR 778.207, other types of contract premium pay distinguished. Paragraph (b) names nightshift differentials in both forms. Paragraph (a) requires their inclusion before overtime is computed and bars crediting them toward it.

Regulation text read from the eCFR current edition, checked September 2026.

Other tools on StateWage