TL;DR

If one of your non-exempt workers bills at two or more skill rates in the same workweek AND crosses 40 hours, the weekly overtime premium is calculated on the weighted-average regular rate — the worker's actual average rate of pay across the week, weighted by hours at each rate.

The straight time on each contract stays at that contract's regular rate. A separate Worker OT Premium line on the invoice carries the half-time premium delta — blended_rate × 0.5 × overtime_hours — on top of the straight-time totals. The math sounds fiddly but is mechanical once the inputs are right.

The mistake is applying time-and-a-half to the higher of the worker's two rates. That over-bills the client and, in DOL parlance, under-pays the worker the actual blended-rate overtime they're owed.

What the rule says

The blended-rate regulation
29 CFR 778.115

"Where an employee in a single workweek works at two or more different types of work for which different straight-time rates have been established, his regular rate for that week is the weighted average of such rates."

Read carefully: weighted average of such rates. Not the higher of the two, not the lower of the two, not whichever the employer prefers. The weighted average — Σ(hours × rate) ÷ Σ(hours).

The federal overtime threshold
FLSA § 7(a)(1) (29 U.S.C. § 207)

The FLSA requires overtime at one and one-half times the regular rate for hours worked in excess of 40 in any workweek, for any non-exempt employee covered by the Act. For multi-rate workers, "the regular rate" is the blended rate computed under 29 CFR 778.115. The 40-hour threshold applies normally; only the regular rate is the weighted average.

The agency enforcement guidance
DOL Field Operations Handbook Ch 32 § 32d05a

The Department of Labor's Wage and Hour Division enforces the blended-rate rule through Chapter 32 of its Field Operations Handbook (the agency's internal enforcement manual). The canonical example in § 32d05a — used below as the worked example — has been the agency reference for decades. Investigators reviewing employer records check this calculation specifically when multi-rate workers appear on the books.

The "regular rate" principle
Walling v. Helmerich & Payne, 323 U.S. 37 (1944)

The U.S. Supreme Court held that the regular rate "must reflect the actual rate of pay" — employers cannot define an artificial "regular rate" by contract or convention if the worker is in fact paid at multiple rates. This is the foundational case that animates 29 CFR 778.115. The weighted-average requirement exists precisely because the alternative — picking whichever rate the employer prefers — would not reflect the worker's actual rate of pay.

The DOL FOH Ch 32 canonical worked example

Maria works for a staffing agency as both a welder ($20/h) and an electrician ($25/h). In one workweek, she logs 30 hours of welding and 20 hours of electrical work — 50 hours total, 10 of which are overtime under the federal 40-hour rule.

Maria, one workweek — 30h welder + 20h electrician DOL FOH Ch 32 § 32d05a; weighted-average rate per 29 CFR 778.115
Contract Rate Hours Straight time
Welder$20.00/h30.00$600.00
Electrician$25.00/h20.00$500.00
Hours
50.00
Straight time
$1,100
OT premium
$110

The blended regular rate is (30 × $20 + 20 × $25) ÷ 50 = $1,100 ÷ 50 = $22.00/h. The overtime premium is $22.00 × 0.5 × 10 hours = $110. Final compensation: $1,100 straight time + $110 OT premium = $1,210.

On the invoice, the welder and electrician contract lines stay at their respective regular rates (the worker is paid straight time for every hour worked at each rate). A separate Worker OT Premium line carries the $110 — that's the half-time premium added on top of the straight-time totals.

The common operator mistake

The most frequent error in multi-rate weeks is computing overtime at the higher of the two rates, not the blended rate. Same Maria, same hours, but the wrong calculation:

The wrong way — OT at the higher rate $25 × 1.5 × 10h = $375 OT premium ($265 over the FLSA-correct $110)
Item Calculation Amount
Welder straight time30 × $20$600.00
Electrician straight time (40h total cap)10 × $25$250.00
Overtime at electrician rate10 × $25 × 1.5$375.00
Total
$1,225
FLSA correct
$1,210
Drift
+$15

The drift looks small per worker per week, but compounds across a roster and across pay periods. More importantly, the wrong-way number isn't just over-billed to the client — it's the wrong total in DOL's reading, because the worker's actual regular rate that week was $22.00/h, not $25/h. A wage-and-hour investigator would flag this as a misclassification of the FLSA premium under § 7(a)(1).

Common mistakes

What you get with TimeCardCruncher

Built for this exact problem

You submit each contract with its own bill rate and a short skill identifier. When the same worker has two or more such contracts in a workweek and crosses 40 hours, we compute the blended regular rate per the FLSA formula, apply the half-time premium to the overtime hours, and add a separate Worker OT Premium line to the invoice that carries the premium delta — distinct from the per-contract straight-time lines so an auditor or your own internal review can trace the calculation. Single-rate weeks (the 95%+ default in staffing) ride through unchanged.