Construction Job Costing & WIP: A Plain-English Guide
Short answer: In construction, two reports decide whether you actually make money: job costing (tracking revenue and every cost against one specific project) and the WIP schedule (a table showing how much of each active job you have truly earned versus billed). Job costing tells you which jobs won or lost. The WIP schedule tells you whether your open work is generating cash or quietly draining it — and it’s the first document a surety or lender reads. Together they turn “did we have a good year?” into “which jobs made money, and why.”
Why whole-company books lie to contractors
Most small businesses can run on one set of books. Construction can’t.
A general set of financials blends every job into one revenue line and one cost line. That’s fine for a coffee shop. But a contractor might have a kitchen remodel earning 22% and a commercial buildout losing 8% running at the same time — and on blended books, they average into one tidy, misleading margin. You look profitable while a job silently bleeds.
The fix is job costing: every project gets its own ledger of labor, materials, equipment, subcontractors, and allocated overhead. Now the losing job can’t hide behind the winners. You see it while there’s still time to change course — not at year-end, after you’ve already bid the next one the same way.
What job costing actually tracks
For each job, you tally the costs that matter in construction:
- Labor — including burden (taxes, benefits, workers’ comp), not just the wage
- Materials — committed costs count, not only what’s been invoiced
- Equipment — owned or rented, allocated to the job that used it
- Subcontractors — including retainage you’re holding or that’s held on you
- Overhead — a fair slice of the costs that keep the whole company running
Set against the contract value and your original estimate, that gives you the number that matters: is this job tracking to the margin you bid, or is it slipping?
The WIP schedule, in one table
Long jobs don’t start and finish in the same month, so you can’t wait until completion to recognize revenue. Construction uses the percentage-of-completion method: you recognize revenue as you earn it.
A WIP schedule lays this out job by job:
| Column | What it means |
|---|---|
| Contract value | What you’ll be paid for the whole job |
| Estimated cost | What you expect it to cost |
| Cost to date | What you’ve spent so far |
| Percent complete | Cost to date ÷ total estimated cost |
| Revenue earned | Contract value × percent complete |
| Billed to date | What you’ve actually invoiced |
| Over / under billing | Earned minus billed |
The last row is the one that reveals your cash reality.
Overbilling vs. underbilling: the number that reveals your cash
- Overbilled — you’ve billed more than you’ve earned. You’re holding the owner’s cash for work you haven’t done yet. It’s a liability, and it can make a struggling company look flush right before the bill comes due.
- Underbilled — you’ve done work you haven’t invoiced. You’re financing the job for your customer out of your own cash. Chronic underbilling is a quiet cash leak that a healthy-looking P&L never shows.
A little overbilling is normal and even healthy for cash flow. Chronic underbilling is a warning light. Either way, you only see it on a WIP schedule.
Why your surety and lender read this first
The WIP report isn’t just for you. A surety underwriter or construction lender reads it before anything else, because it shows whether your open jobs are healthy or hiding trouble. Clean, accurate WIP reporting is what expands your bonding capacity and credit line — which is what lets you take on bigger work. Sloppy WIP does the opposite.
Add retainage — the 5–10% of each payment an owner withholds until substantial completion — and you can see why a “profitable” contractor still runs short on cash. That mechanic is exactly why winning more work can bankrupt a contractor who isn’t watching these numbers.
Software helps — discipline decides
QuickBooks with job costing, Sage, Foundation, or a project tool like Procore feeding your books can all produce these reports. But the software isn’t the answer; the setup and the monthly rhythm are. Right cost codes, committed costs captured as they happen, a WIP schedule refreshed every month — that’s what turns raw transactions into a number you can bid and borrow against. (If you’re comparing tools, our real-estate software guide covers adjacent picks.)
This is the part most contractors don’t have time to run consistently while also running crews. It’s the same reason profitable businesses still run out of cash: the numbers exist, but nobody’s turning them into a decision every month.
That’s the work we do. DaxHive keeps your construction books structured for job costing, produces a monthly WIP schedule, and keeps your surety and lender reports ready — while you own every account. It’s one piece of a whole outsourced back office built for contractors, delivered through our bookkeeping service.
Want to see which of your jobs actually make money? Book a free discovery call and we’ll walk through setting up job costing and a monthly WIP — and what it costs.
Frequently asked questions
What is job costing in construction? +
Job costing is tracking revenue and every cost against one specific project instead of lumping everything into your whole-company books. Each job gets its own tally of labor, materials, equipment, subs, and overhead, so you can see whether that job actually made money rather than guessing from a blended year-end margin.
What is a WIP schedule in construction accounting? +
A WIP schedule, or work-in-progress report, is a table listing your active contracts with their contract value, estimated cost, costs incurred to date, percent complete, and revenue earned. It tells you how much of each job you have really earned versus how much you have billed, which is the truest read on whether your jobs are generating or burning cash.
What is the percentage-of-completion method? +
Percentage of completion recognizes revenue on a long job as you complete it, rather than all at once at the end. You divide costs incurred to date by total estimated cost to get percent complete, then multiply the contract value by that percentage to find revenue earned so far. It is the standard method for long-cycle construction contracts.
What is the difference between overbilling and underbilling? +
Overbilling means you have billed more than you have earned, so you are holding the owner's cash for work not yet done. It shows as a liability. Underbilling means you have done work you have not yet billed, so you are financing the job for your customer. Both distort your profit picture until the WIP schedule corrects them.
Why do lenders and sureties want a WIP report? +
A surety underwriter or construction lender reads the WIP report first because it shows whether your open jobs are healthy or hiding losses. Overbillings can mask a cash problem, and underbillings can hide profit erosion. The WIP is the document that decides your bonding capacity and credit line, so accurate WIP reporting directly affects how much work you can take on.
How often should a contractor update job costing and WIP? +
Monthly at minimum, and weekly for labor and committed costs on active jobs. Costs move fast in construction, and a WIP schedule built on stale numbers gives false comfort. Updating monthly lets you catch an underbid or a slipping job while there is still time to change course rather than at year-end.
What is retainage and how does it affect job costing? +
Retainage is a portion of each payment, usually 5 to 10 percent, that the owner withholds until the job is substantially complete. It matters for job costing because a job can look profitable on paper while a meaningful slice of its cash sits unpaid until the end, so your WIP and cash forecast both need to account for it.
Do small contractors really need job costing? +
Yes. Even a two-crew remodeler benefits, because a single underbid or rework-heavy job can quietly erase the margin from several clean ones. Job costing is what turns did we have a good year into which jobs made money and which lost it, and that answer is what lets you bid the next one better.
Can DaxHive set up job costing and WIP for my construction business? +
Yes. DaxHive keeps construction books structured for job costing and produces a monthly WIP schedule, so profit shows up per job and your surety and lender reports are ready when you need them. You own every account; we run the bookkeeping behind it. You can book a free discovery call to see how it would work.
What accounting software works for construction job costing? +
Common choices include QuickBooks with a job-costing setup, Sage 100 and 300 Contractor, Foundation, and project tools like Procore or Buildertrend that feed the accounting system. The software matters less than the setup and discipline behind it; the right cost codes and a consistent monthly WIP process are what actually produce reliable numbers.
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