What Percentage-of-Completion Accounting Means for Contractors

What Percentage-of-Completion Accounting Means for Contractors

A contractor can finish the year with a full pipeline, a fat bank balance, and books that say the business made money — and still be quietly broke. The reason is almost always the same: the books are counting cash instead of counting progress.

That gap is exactly what percentage of completion accounting explained correctly is supposed to close. It's the method that ties revenue to the work you've actually done, not to whatever showed up in the bank this month. For most contractors running jobs that span more than a few weeks, it isn't optional — it's the method the IRS and GAAP expect you to use.

Here's what that actually means, in plain English, and why getting it wrong caps the one number that decides how big a job you can chase: your bonding line.

Percentage of completion accounting, explained: revenue follows the work

Cash-basis books treat money as income when it lands. Deposit hits, revenue goes up. Pay a supplier, profit goes down. That's fine for a coffee shop. For a contractor running a nine-month job with a 30% deposit up front, it's a fun-house mirror.

Percentage-of-completion fixes this by recognizing revenue as the job progresses. If you're 40% of the way through the work, you book 40% of the contract's revenue — and you match it to the costs you incurred getting there. The progress drives the profit.

This is the heart of construction revenue recognition: a half-finished job should show roughly half its profit, not all of it or none of it. The method exists so the income statement tells the truth while the building is still going up.

The math is simpler than it sounds: cost-to-cost

There's one dominant way to measure "how far along am I," and it's called the cost-to-cost method. The formula:

Costs incurred to date ÷ total estimated costs = percent complete.

Say a job is contracted at $1,000,000 with $800,000 in total estimated costs. You've spent $400,000 so far. That's $400,000 / $800,000 = 50% complete. So you recognize 50% of the revenue — $500,000 — to date.

That's it. Costs you've actually burned, divided by what you expect to burn in total. The percentage that falls out is the percentage of revenue you've earned. Both the tax method under IRC §460 and the GAAP standard, ASC 606, lean on this kind of input measure to decide how much revenue belongs to the period.

Why the IRS basically requires percentage-of-completion accounting

Under IRC §460, income from a long-term construction contract — generally one that starts in one tax year and finishes in another — must be reported on the percentage-of-completion method. Long-term doesn't mean years. It means it crosses a year-end.

There's a carve-out for smaller contractors. A "small construction contract" — broadly, a contract you expect to complete within two years, performed by a contractor whose average annual gross receipts for the prior three years fall under an inflation-adjusted threshold (in the low $30-millions in recent years) — is exempt and can use a different method. Verify your specific year's threshold with your CPA, because it moves with inflation.

But here's the thing: even contractors who can use a simpler tax method usually shouldn't run their actual books that way. Which brings us to the part that decides whether you can grow.

Cash-basis books cap your bonding line

Sureties and banks don't lend against your bank balance. They lend against your financial statements — specifically, your balance sheet and your job-cost reporting. If those statements run on cash, every job's profit is misstated, your equity looks lumpy and unreliable, and the surety can't tell a profitable contractor from a lucky one.

The result is a smaller bonding line than your business actually deserves. You get capped at jobs you've already outgrown, watching bigger ones go to competitors whose books a surety can trust.

Percentage-of-completion produces statements a surety can underwrite. That's not a compliance nicety. It's the difference between bidding a $2M job and a $6M one.

Overbillings and underbillings: the entries that catch the lie

When revenue follows progress and billing follows a payment schedule, the two almost never match in a given month. The difference has a name, and it lives on the balance sheet — not the income statement.

• Overbilling (a liability): you've billed the client more than the work you've earned. That's money you owe back in work. It shows up as "billings in excess of costs and estimated earnings."
• Underbilling (an asset): you've earned more than you've billed. The client owes you for work already done. It shows as "costs and estimated earnings in excess of billings."

These balancing entries are the whole point of a WIP schedule explained properly: a job-by-job report that reconciles what you've earned against what you've billed. A heavily overbilled book is a warning — it often means you're financing future work with money you've already collected, and the profit isn't as real as it looks.

The estimate is the load-bearing wall

Cost-to-cost has one obvious dependency, and it's the thing that wrecks otherwise-clean books: the total estimated cost.

If your total-cost estimate is wrong, your percent complete is wrong, so your recognized revenue is wrong, and every job on the schedule inherits the error. Lowball the estimate and you'll over-recognize profit early — then eat a brutal correction at closeout when reality arrives. A "10% profit fade" from estimate to actual isn't a rounding issue; it's a forecasting failure that surfaces in your WIP.

This is why percentage-of-completion is only as honest as the estimating discipline behind it. The accounting doesn't create accuracy. It exposes whether you have it.

Get books a surety will actually trust

Percentage-of-completion isn't hard math. It's disciplined math — done every month, job by job, by someone who knows construction and not just spreadsheets. Most general bookkeepers have never built a WIP schedule, and it shows the first time a surety asks for one.

Steady Co builds accounting, tax, and fractional-CFO support around exactly this kind of work — bringing Big 4 rigor and real industry experience to contractors who need their books to hold up under a banker's and a surety's eyes. They're the kind of firm that treats a WIP schedule as a management tool, not a year-end chore.

If your books are still on cash and your bonding line feels smaller than your ambition, that's the gap to close first. Read Steady Co's verified reviews on Sam's List and book an intro call — bring a recent job-cost report, and ask them what your WIP would say about your last big project.