The Contractor WIP Schedule, Explained
By SubcontractorHub Editorial Team·Published August 2026
Quick Answer
A WIP schedule takes four inputs per open job — contract value, cost to date, estimated total cost, and billed to date — and derives percentage complete (cost ÷ estimated cost), earned revenue (contract × percentage complete), and the over/underbilling variance (billed − earned). Positive is overbilled, negative is underbilled. It is the report that shows whether your profit is earned or borrowed, and it drives your bonding capacity. Build one now with the free WIP calculator →
Plenty of contractors run for years without a WIP schedule and never feel the absence, because the income statement looks fine. The problem is that on contract work the income statement can look fine for a long time while the business quietly gets worse, and the WIP is the report that would have said so. It is also the first document a surety or a lender asks for, which means a contractor without one is negotiating for capacity without the evidence that decides it.
The mechanics are simpler than the reputation suggests — four inputs and two calculations. What makes it demanding is not the arithmetic but the honesty required in one of the inputs.
The Four Inputs
The Two Calculations
Percentage complete = cost to date ÷ estimated total cost
Earned revenue = contract value × percentage complete
Variance = billed to date − earned revenue (positive = overbilled, negative = underbilled)
Take a job with an $840,000 contract, $512,000 spent, $745,000 estimated total cost, and $590,000 billed. Percentage complete is 512 ÷ 745 = 68.7%. Earned revenue is 840,000 × 68.7% = $577,000. You have billed $590,000, so you are overbilled by about $13,000 — modest and unremarkable. Gross profit at completion is 840,000 − 745,000 = $95,000, an 11.3% margin, of which roughly $65,000 has been earned so far.
Run your own portfolio through the WIP schedule calculator — it totals the over- and underbillings separately, which is more informative than a net figure, because a portfolio can net to roughly zero while containing one badly underbilled job.
The Estimated Total Cost Is the Whole Report
Everything downstream depends on this one number, and it is the only input that is a judgement rather than a record. Understate it and percentage complete overstates, earned revenue overstates, and the job looks more profitable than it is — right up until closeout, when the overrun arrives all at once.
This is why a WIP built on original bid figures is not a forecast. If the estimated total cost on a job has not moved in four months, nobody is forecasting it; they are copying it. The discipline that makes the report worth producing is a monthly conversation with whoever is running each job about what it will genuinely take to finish — and that conversation tends to be more valuable than the number it produces.
Reading Over- and Underbilling Properly
Overbilling means you have billed ahead of production. In isolation it is good practice — you are financing the job with the owner's money instead of your own. The danger is concentration rather than existence. When a large share of the portfolio is overbilled, the bank balance is revenue that has already been collected against work still to be performed, so as those jobs close the billings stop while payroll does not. This is how contractors fail while showing a profit, and it is why lenders read the WIP rather than just the income statement.
Underbilling is the more revealing signal, because it is almost never intentional. Work performed but unbilled usually traces to one of three causes:
- Change orders performed before approval. The cost lands immediately while contract value cannot rise until the change is executed, so the job flips underbilled in one period.
- Missed billing deadlines. A draw submitted after the cut-off waits a full cycle, and the WIP shows the work as earned but unbilled meanwhile.
- A cost overrun recognised late. Raising estimated total cost raises percentage complete against an unchanged contract value, which raises earned revenue and can push a job from overbilled to underbilled without anything happening in the field.
The first cause is the most common and the most fixable. Price the change, get it approved, add the line to the schedule of values, then build. The change order calculator prices the impact and the schedule of values calculator shows where it lands in the next draw.
What a Surety Underwriter Actually Looks For
Bonding capacity is set largely off this schedule, and underwriters read it for pattern rather than for any single figure. Three things stand out to them: large underbillings, which suggest unbilled change orders or absorbed overruns; heavy overbillings, which suggest dependency on advance billing for working capital; and estimated costs revised upward late in a job, which says the contractor's own forecasts are optimistic.
The practical implication is worth stating plainly: a consistent, conservatively forecast WIP will usually buy more capacity than a single strong year of profit. Underwriters are pricing the risk that you do not know where your jobs stand, and a clean WIP is the evidence that you do. Retainage receivable belongs in that picture too — quantify it with the retainage calculator.
Why the Report Is Usually Wrong, and What Fixes It
Most bad WIP schedules are not bad arithmetic — they are downstream of scattered job cost data. When labour hours sit in one system, supplier invoices arrive in another, and change orders live in an email thread, the monthly WIP becomes a reconciliation performed partly from memory. That is how a job reaches 90% complete before anyone notices the cost forecast was stale for a quarter.
The fix is upstream. Costs captured against the job as they happen, change orders approved before work starts, and billings recorded at certified amounts turn the WIP into a report you run rather than one you rebuild. See project management, construction billing software, and commercial contractor software for how the pieces connect — and financing for bridging the gap that retainage creates in the meantime.
Frequently Asked Questions
What is a WIP schedule for contractors?
A work-in-progress schedule lists every open contract with four inputs — contract value, costs incurred to date, estimated total cost at completion, and amount billed to date — and derives percentage complete, revenue earned, gross profit at completion, and whether each job is overbilled or underbilled. It is the report sureties, lenders, and CPAs ask for first, because it is the only one that shows whether reported profit has been earned or borrowed from future billings.
How do you calculate percentage complete for a WIP schedule?
The standard approach is cost-to-cost: costs incurred to date divided by estimated total cost at completion. Spend $600,000 against an estimated $1,000,000 total cost and the job is 60% complete, so you have earned 60% of the contract value as revenue. Note that this is deliberately independent of billings — that separation is the entire point, because comparing earned revenue against what you have actually billed is what exposes over- and underbilling.
What does it mean to be overbilled on a job?
Overbilled — formally 'billings in excess of costs and estimated earnings' — means you have invoiced more than you have earned based on progress. It appears as a liability on the balance sheet and it funds your operations with the customer's money, which is normal and generally healthy. The risk is concentration: when much of the portfolio is overbilled, today's cash is future revenue already collected, so as those jobs close the billings stop while costs continue.
Is underbilling worse than overbilling?
Usually, because it is almost never deliberate. Underbilling means you performed work you have not billed for, and the common causes are all management failures: change orders executed in the field before approval, missed billing deadlines, or a cost overrun that has not been reflected in the forecast. Overbilling is at least a decision. Underbilling is generally something that happened to you, which is why underwriters treat a large underbilling as a warning sign.
Why do bonding companies ask for a WIP schedule?
Because bonding capacity depends on whether a contractor's profit is real, and only the WIP shows that. A surety underwriter reads it for three signals: large underbillings suggesting unbilled change orders or hidden overruns, heavy overbillings suggesting cash dependency on advance billing, and estimated costs revised upward late in a job, which indicates optimistic forecasting. A consistent, conservatively forecast WIP supports a larger bonding line than one strong year of profit.
How often should contractors update their WIP schedule?
Monthly at minimum and aligned to the billing cycle, with the estimated total cost genuinely re-forecast rather than carried forward. A WIP where the cost estimate never changes is not a forecast — it is a copy of the original bid, and it will conceal an overrun until closeout. The monthly conversation about what each job will really cost to finish is usually more valuable than the report itself.
What is the difference between a WIP schedule and a job cost report?
A job cost report looks backward: what has been spent against each cost code. A WIP schedule looks forward: given costs to date and a forecast of total cost, how complete is the job, how much revenue has been earned, and how does that compare with billings. Job cost is an input to the WIP. Many contractors produce accurate job cost reports and still have no WIP, which is why cost overruns are discovered at closeout rather than in month three.
Can you produce a WIP schedule from QuickBooks alone?
Partially, and that gap is where most contractors struggle. Accounting packages hold costs and billings well, but the estimated total cost at completion is a project-management judgement that lives outside the ledger, and without a current forecast the percentage complete is unreliable. Contractors who produce trustworthy WIP reports capture costs against the job as they happen and revise the completion forecast monthly, then bring both into the accounting system.
Related Guides
- Construction Progress Billing: AIA G702/G703
- Construction Retainage Explained
- How to Bid Construction Jobs
- WIP Schedule Calculator
- Schedule of Values Calculator
- Retainage Calculator
- Change Order Calculator
- Invoice Factoring for Contractors
- Mechanical Contractor Software
- → Construction Billing Software
- → Commercial Contractor Software
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