WIP Schedule Construction: A GC's Guide to Job Costing

You're busy. Three crews on the ground, the phone keeps going, and you signed a new contract last week. Business looks good from the outside. Then you open your bank account and wonder where the money went.

This happens to GCs who are running profitable operations. You can be winning work, staying booked, and still come up short on operating cash — miss payroll, or watch what should have been a good year turn into something your accountant can't explain. The WIP schedule is the diagnostic tool that tells you exactly why this happens, job by job, before it becomes a crisis.

This guide covers what a WIP schedule actually contains, how to build one from scratch, how it connects to your job costing discipline, and which tools make the process sustainable. If you're running your business off a P&L and a gut feeling, this is worth your time.

What a WIP Schedule Tells You That Your P&L Doesn't

Your profit and loss statement tells you what revenue you recognized and what costs you incurred over a period. Useful — but it doesn't tell you whether that revenue was actually earned or just billed. It doesn't tell you which jobs are bleeding margin right now. And it won't tell you whether your cash position reflects real project progress or aggressive invoicing.

A WIP schedule is a real-time snapshot of every active job's billing position and profitability. It answers two questions at once: how much revenue have you actually *earned* based on work completed, and how much have you *billed*? The gap between those numbers is where your cash problems live.

Think of the P&L as a rearview mirror — a WIP schedule is the windshield.

Over-Billing vs. Under-Billing

When you've billed more than you've earned, you're overbilled. That excess isn't income — it's a liability.

Say you have a $500,000 contract. You've billed $300,000, but your cost-to-cost calculation shows you've only earned $240,000 in revenue. That $60,000 gap is money collected for work you haven't done yet. If the job hits a scope dispute, a termination, or a change order that doesn't get approved — you may have to give it back. Overbilling can look like healthy cash flow while quietly building a balance sheet liability.

Underbilling is the other direction. You've completed $300,000 worth of work but only billed $220,000. That $80,000 is real — earned revenue sitting uncollected — but it doesn't show up on your P&L. It shows up as a cash shortage when you're trying to make payroll.

Why Profitable Jobs Can Still Kill Your Cash Flow

A GC can carry a 12% gross margin on paper and still be 90 days behind on supplier payments.

Three jobs running simultaneously, all underbilled by $75,000–$100,000 each. Each one profitable by estimate. But you front-loaded costs — labor, materials, sub mobilization — without billing fast enough to match. That's $225,000–$300,000 in earned revenue sitting uncollected across your portfolio, and your bank account reflects none of it.

A GC running commercial tenant improvement work told me about this situation: he was making money on every job, could see it in the numbers, but was constantly tapping his line of credit to make payroll. His CPA eventually built a WIP schedule and found he was chronically underbilled by around $180,000 at any given time. Not a failing business — a billing discipline problem. The WIP schedule was what surfaced the difference.

The Eight Columns Every WIP Schedule Needs

Every column earns its place. Skip one and the whole picture distorts.

• Original Contract Value — the signed amount before any changes
• Revised Contract Value — original contract plus approved change orders; your current total
• Estimated Cost at Completion (EAC) — your best current forecast of total project cost when the job is done
• Cost to Date — actual costs incurred through the reporting period
• Percent Complete — Cost to Date divided by EAC
• Earned Revenue — revenue actually earned based on percent complete
• Billed to Date — what you've invoiced the owner
• Over/Underbilling — the difference between Earned Revenue and Billed to Date

Updated monthly, these eight columns give you a complete financial picture of every active job. The AICPA's guidance on percentage-of-completion accounting — which underpins WIP reporting — makes clear this structure isn't optional for GCs recognizing revenue on long-term contracts.

Which Percent Complete Method Should You Use?

The method you choose determines how accurate every downstream number will be.

Cost-to-cost divides actual cost incurred by estimated cost at completion. It's the GAAP-preferred method for most general contractor work because it ties directly to financial data you already track and is fully auditable. Units completed works well for repetitive scopes — concrete pours, framing panels — where physical output is measurable. Supervisor estimate is the most subjective and the most prone to optimism bias.

For most GCs, cost-to-cost is the right default. Reserve units-based methods for specific scopes where output is clearly measurable. Save supervisor estimates for situations where cost data genuinely isn't available — don't use them as a shortcut.

The Column Most Likely to Be Quietly Wrong: EAC

The Estimated Cost at Completion is the most consequential number on your WIP schedule.

If your EAC is understated, percent complete is overstated, earned revenue is inflated, and your WIP schedule is lying to you. A job that's actually 55% complete looks 70% on paper. You bill accordingly. Then the final 30% of the job costs twice what you planned, and you're staring at a loss that nobody saw coming until the last month of the project.

This is margin fade — not one dramatic event, but a series of small, optimistic EAC updates that go unchallenged because the job *feels* like it's going well. Require field-verified cost forecasts, not just accounting actuals, updated every month. That's what keeps the EAC honest.

How to Build a WIP Schedule: Step by Step

Building your first WIP schedule is a one-time learning curve. The math is straightforward. The discipline is what most GCs are missing.

Step 1 — Gather Job Cost Data for Every Active Project

You need four inputs per job: committed costs (subcontract values plus purchase orders), actual costs to date (labor, materials, subs paid), pending subcontractor invoices not yet posted, and approved change orders. Pull this from job cost reports in QuickBooks, Sage 100 Contractor, or Procore as of a consistent date — typically the last day of your billing period.

Don't skip the pending invoices. If your framing sub submitted a $40,000 draw that hasn't been posted yet, your cost-to-date is understated and your percent complete will be off.

Step 2 — Calculate Percent Complete and Earned Revenue

The formula: (Cost to Date ÷ Estimated Cost at Completion) × Revised Contract Value = Earned Revenue

A worked example: $1,200,000 contract, $1,050,000 EAC, $630,000 cost to date.

• Percent complete: $630,000 ÷ $1,050,000 = 60%
• Earned revenue: 60% × $1,200,000 = $720,000

That's the revenue you've actually earned — regardless of what you've billed.

Step 3 — Find Your Billing Position on Each Job

Subtract Billed to Date from Earned Revenue. Positive result means you're underbilled — issue a draw immediately. Negative result means you're overbilled — track it as a liability, not income.

Using the example above: billed $780,000 against $720,000 earned means you're overbilled by $60,000. Billed $650,000 means you're underbilled by $70,000 — and that's cash you should be collecting right now.

Step 4 — Update Monthly, Without Exception

The most common reason GCs skip WIP updates is time. That's a real constraint. But a quarterly schedule is too slow to catch margin fade before it's unrecoverable. Monthly is the minimum cadence that gives you a chance to act.

Tie your WIP update to your billing cutoff date. When you're pulling draws, you're already touching cost data — that's the moment to update the schedule. Purpose-built software like Procore or Bidi can automate the data pull and cut the monthly update from a half-day task to under an hour.

Job Costing Construction: How WIP and Cost Codes Work Together

A WIP schedule is only as accurate as the job costing structure feeding it. Garbage in, garbage out.

Your WIP pulls from job cost reports. Those reports only mean something if your cost codes are set up correctly, used consistently, and actually reflect where money is going in the field. This is one of those things that looks fine in theory and drifts badly in practice.

The Cost Code Problem That Creeps Up Around Year Three

By the time a GC is running $5M–$10M in annual volume, the original cost code structure has usually been patched, expanded, and partially abandoned. Field staff post costs to whatever code is closest. PMs create new codes mid-job to handle scope changes. Overhead gets buried in direct cost codes to make job margins look cleaner on paper.

The result: EAC inputs are built on inconsistent historical data, cost-to-date figures don't match physical progress, and your WIP schedule produces numbers that feel wrong but are hard to argue with because the data looks clean. Fix this with an annual cost code audit and field-level training that connects code discipline to the financial reports leadership actually uses.

Turning WIP Actuals Into Better Estimates

When a job closes, your final WIP schedule contains actual cost-to-complete by trade, actual margin versus estimated margin, and the timeline of any overruns. That's a direct feedback loop into your next bid — and most GCs never use it.

If your mechanical scopes consistently run 8% over estimate, your next mechanical budget should account for that. If your concrete work always comes in under, you know where your competitive edge is. This is how job costing construction becomes a compounding advantage: each project makes the next estimate more accurate. For more on how precise quantity takeoffs feed cleaner estimates and better WIP accuracy, see the guide on material takeoff construction.

Construction KPIs to Track Alongside Your WIP Schedule

Four metrics belong on every GC's dashboard alongside the WIP schedule: backlog by month, gross margin by job, billing velocity (days between work completed and invoice submitted), and cost variance by trade. Each one tells you something the others don't.

How the WIP Schedule Exposes Margin Fade in Real Time

CFMA's annual financial benchmarking study puts median net profit margins for general contractors at 2%–6%, depending on volume and specialty. That's a thin band. A single job that fades from 8% gross margin to 3% can move your company-level net margin by a full percentage point if it's a large enough contract.

The WIP schedule catches this because it recalculates earned revenue and implied margin every month as the EAC is updated. If a job that estimated at 10% gross margin is trending toward 4% by month three, you see it now — not at closeout. That's the difference between a course-correction conversation with your PM and a year-end write-off. For more on managing margin at the job level, see construction project profitability.

The Underbilling Ratio: An Overlooked Red Flag

A high underbilling ratio relative to total backlog is one of the most overlooked warning signs in construction cash flow management.

If you have $2M in underbilled work across your portfolio and only $800,000 in new work under contract, you're depending on collecting past-due earned revenue to fund future operations. That's a fragile position.

Watch this number monthly. When underbilled work exceeds 15–20% of your total backlog, it's time to accelerate billing on active jobs and tighten your draw schedule with owners. Don't wait for the bank account to deliver that news.

WIP Schedule Software: Spreadsheet vs. Purpose-Built Tools

Every GC starts with a spreadsheet. Some stay there forever. Whether that's reasonable depends on how many jobs you're running and how clean your cost data is.

When a Spreadsheet Holds Up — and When It Doesn't

Four or fewer concurrent jobs, consistent cost code discipline, one person managing the WIP update: a well-built Excel or Google Sheets template is a legitimate choice. The math isn't complex. The risk is human error — a wrong formula, a stale EAC, two people editing the same file at once.

Once you're running five or more concurrent jobs, or more than one person is touching cost data, a spreadsheet becomes a liability. Version conflicts, manual entry errors, and the time cost of pulling data from multiple sources add up. At that scale, the question isn't whether to upgrade — it's which tool fits your workflow.

Comparison: WIP Reporting Across Common GC Tools

Frequently Asked Questions About WIP Schedules in Construction

How often should a GC update their WIP schedule?

Monthly is the minimum, tied to your billing cutoff date — not done whenever someone finds time. Quarterly WIP updates are too slow to catch margin fade before it becomes unrecoverable. By the time a quarterly schedule shows a problem, you've missed two or three billing cycles where you could have intervened. If you're running more than $3M in active work, consider a bi-weekly review of your largest jobs even if the full schedule updates monthly.

What's the difference between a WIP schedule and a schedule of values?

A schedule of values (SOV) is a billing document — what you submit to the owner to justify your draw request, broken down by line item or CSI division. A WIP schedule is an internal accounting and management tool that measures earned revenue against billed revenue across all active jobs. They use similar line items and both reference percent complete, but they serve completely different purposes. The SOV is for the owner's approval process; the WIP schedule is for your own financial control. Treating billing documents as financial reports is a construction accounting basics mistake that catches up with a lot of growing GCs.

How do auditors and bonding companies use your WIP schedule?

Sureties and CPAs treat the WIP schedule as a credibility document. Auditors verify that revenue recognition follows percentage-of-completion accounting correctly — they're looking for inflated EACs, aggressive overbilling, and jobs where the numbers don't match field reports. Bonding companies use it to assess whether your reported backlog and profitability are real. A GC who produces a clean, consistently updated WIP schedule signals financial discipline. One who can't — or whose schedule shows chronic overbilling — can expect scrutiny that affects bonding capacity and credit terms.

What does a large underbilling position mean for my bonding capacity?

Counterintuitively, chronic underbilling can shrink your bonding capacity even when you're doing strong volume. Sureties look at working capital, recognized revenue, and backlog coverage ratios. If a large portion of your earned revenue is sitting as underbilled work — an asset on the balance sheet but not yet cash — your financial ratios look weaker than your actual business performance warrants. Aggressive, accurate billing isn't just a cash flow move. It's a bonding strategy.

Can I use my WIP schedule to improve construction cash flow management?

Yes — this is one of the most practical uses of the schedule. When you identify underbilled jobs in your monthly WIP review, that's your trigger to issue draws immediately. Don't wait for the next scheduled billing date if you've already earned the revenue. The WIP schedule also lets you time subcontractor payments against incoming draws, so you can sequence outgoing payments against cash you know is coming in.

What if my WIP schedule hasn't been updated in months?

Don't try to reconstruct history — it's not worth the time and the numbers won't be reliable. Start with your five largest jobs by contract value, rebuild the EAC from current field conditions (talk to your PMs, not just the accounting system), and reconcile billing records against what's been paid. Get those jobs current before your next financial close, then work down to smaller jobs over the following two months. The goal is accuracy going forward, not a perfect historical record.

The WIP Schedule Is Your Early Warning System — Use It Like One

Most GCs treat the WIP schedule as an accounting obligation — something the CPA asks for twice a year that lives in a spreadsheet nobody loves. That framing is costing you money.

A properly maintained WIP schedule is the earliest warning system you have for margin fade, cash pressure, and billing gaps. It tells you which jobs need attention before the field does. It gives your bonding company confidence. It sharpens your next estimate because it captures what your last job actually cost. And it turns construction KPIs from abstract metrics into decisions you can act on this week.

The accuracy of your WIP schedule starts with the quality of your cost data — and that starts with how cleanly your bids are structured from day one. If you want to see how faster, cleaner bid management feeds more accurate job costing and WIP reporting from the start of every project, book a demo at bidicontracting.com.