the fringe credit mistake that becomes back wages

Why the divisor has to be every hour

Here is the idea in ordinary terms. You pay $20,900 a year for someone's health plan. That plan covers them for the whole year — all 2,080 hours they work, not just the weeks they happen to be on a government job.

So the hourly value of that plan is $20,900 ÷ 2,080 = $10.05 an hour. That is the credit you can take against the fringe you owe.

Now suppose only 760 of those hours were on the public job. If you divide by 760 instead, you get $27.50 an hour of “credit”. But you did not spend $27.50 an hour on that person's benefits. You spent $10.05. The extra $17.45 is imaginary.

And the imaginary part has a real consequence: you took credit for it, so you paid $17.45 an hour less in cash fringe than you owed. Multiply by 760 hours and that is $9,653 of back wages for one employee.

There is a principle behind the rule, too. If you could divide by public hours only, the government job would be paying for benefits the worker also enjoys on private work — which is precisely the subsidy the rule exists to prevent.

The same crew, both ways

Six employees, real plan costs, real hour splits. The exposure column is what you would owe in back wages.

Look at the pattern rather than the total. The smaller someone's Davis-Bacon share of the year, the worse the error gets. S. Petrov worked only 22% of the year on public work, and the wrong divisor inflates their credit by more than four times.

Which means the exposure is largest for exactly the employees you think about least — the ones who only occasionally touch a federal job.

The other rule people get wrong: overtime

Overtime on prevailing wage work has a rule that looks fiddly and is actually simple.

The overtime premium applies to the base rate only. The fringe is never multiplied by 1.5. You owe the fringe on every hour at its flat rate, including overtime hours, because the fringe is a benefit cost and benefits do not accrue faster in hour 41.

Get that backwards and you overpay, which is at least not a liability — but combined with an inflated fringe credit it can mask the underpayment underneath.

The workbook also handles split classifications: someone who works part of a week as an electrician and part as an apprentice, at different determined rates.

How to calculate a Davis-Bacon fringe credit

hourly fringe credit = annual plan cost / TOTAL annual hours

What is inside the file

Eight tabs, with a six-person crew filled in — deliberately including people whose Davis-Bacon share ranges from 22% to 87% of the year, because that spread is where the error lives.

Opening it in Excel, Google Sheets or Numbers

It is one .xlsx file. There are no macros, no add-ins and nothing to install, which is what makes it portable — a macro-driven template would be Excel-only.

Every formula in this workbook uses ordinary functions — SUM, IF, INDEX, MATCH and their relatives. Nothing here is Excel-only.

The arithmetic, written out

One line is the product. The rest follows from it.

hourly fringe credit = annual plan cost / TOTAL annual hours worked

credit claimed       = MIN(hourly fringe credit, required fringe rate)
cash fringe owed     = required fringe rate - credit claimed
overtime pay         = base rate x 1.5        # fringe is NEVER x1.5
gross                = (base x hours) + (premium x OT hours) + (fringe x all hours)

And the exposure calculation used in the table above:

exposure = (wrong credit - right credit, each capped at the required fringe)
           x Davis-Bacon hours

The capping matters. You cannot claim more credit than the fringe you owe, so an absurd “credit” of $50.98 does not create $50.98 of exposure — it creates exposure up to the fringe rate. The workbook caps it, which is why the numbers in that table are lower than a naive subtraction would give.

How I know the numbers are right

Every figure on this page comes from the workbook's own checker, which reimplements the calculation in Python and diffs it against the recalculated file — including a separate test for negative and edge-case inputs.

The seeded crew was built to exercise the range rather than to produce a dramatic total: hour splits run from 410 Davis-Bacon hours out of 1,880 up to 1,840 out of 2,120, so you can see the error growing as the public share shrinks. That relationship is the thing worth understanding, and a tidier example would have hidden it.

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