Overbilling vs Underbilling in Construction: What Contractors Need to Know

Every construction company bills its clients on a schedule — usually monthly, tied to the percentage of work completed. But the amount you bill and the amount of work you have actually completed are rarely in perfect alignment. When they diverge, you are either overbilled or underbilled. Both conditions are common in construction. Both can create serious financial problems if they go unmanaged. This guide explains what overbilling and underbilling mean, how they happen, why both are dangerous, and what contractors need to do to keep their billing positions under control.

What Is Overbilling in Construction?

Overbilling occurs when a contractor bills a client for more than the value of work actually completed to date. In other words, you have collected or invoiced revenue that exceeds the earned portion of the contract based on the percentage of completion.

Overbilling is sometimes called billings in excess of costs or billings in excess of earned revenue. On a WIP schedule, it shows up when the billed percentage is higher than the completion percentage. On the balance sheet, overbilling is classified as a current liability — because you owe that work to the client. You have been paid for something you have not yet delivered.

Overbilling is extremely common in construction. Some contractors overbill intentionally to front-load cash flow. Others overbill unintentionally because their pay applications do not accurately reflect the work completed. Either way, overbilling creates a financial obligation that must be fulfilled through future work — and if costs end up higher than expected, the money may already be spent.

What Is Underbilling in Construction?

Underbilling is the opposite. It occurs when a contractor has completed more work than has been billed. You have incurred costs and earned revenue, but you have not yet invoiced the client for the full value of the work performed.

Underbilling is also called costs in excess of billings or earned revenue in excess of billings. On the WIP schedule, it appears when the completion percentage exceeds the billed percentage. On the balance sheet, underbilling is classified as a current asset — because the client owes you for work you have already performed.

Underbilling starves your cash flow. You have spent money on labor, materials, subcontractors, and equipment, but the corresponding revenue has not been collected. If you are chronically underbilled across multiple projects, your company can run out of cash even while showing a profit on paper.

How Overbilling Happens: A Numeric Example

Consider a contractor working on a $1,000,000 contract with an estimated total cost of $800,000. At the end of month three, the numbers look like this:

• Contract value: $1,000,000
• Estimated total cost: $800,000
• Actual costs incurred to date: $240,000
• Percent complete (cost method): $240,000 / $800,000 = 30%
• Earned revenue (30% of contract): $300,000
• Amount billed to date: $400,000

The contractor has billed $400,000 but has only earned $300,000 based on the work completed. The difference — $100,000 — is the overbilling. The contractor has collected $100,000 more than the value of work performed.

How does this happen? The project manager may have front-loaded the billing schedule, requesting payment for materials stored on site, mobilization costs, or early-phase work at inflated percentages. The client may have approved pay applications without closely verifying the completion percentages. Or the estimator may have weighted the schedule of values so that higher-margin items are billed first.

On the surface, the contractor's cash position looks strong — $400,000 collected against only $240,000 spent. But that extra $100,000 in overbilling is not profit. It is an advance against future work that still needs to be performed.

How Underbilling Happens: A Numeric Example

Now consider a different project — a $500,000 contract with an estimated total cost of $400,000. At the end of month two:

• Contract value: $500,000
• Estimated total cost: $400,000
• Actual costs incurred to date: $200,000
• Percent complete (cost method): $200,000 / $400,000 = 50%
• Earned revenue (50% of contract): $250,000
• Amount billed to date: $175,000

The contractor has earned $250,000 in revenue based on 50 percent completion, but has only billed $175,000. The difference — $75,000 — is the underbilling. The contractor has performed $75,000 more work than has been invoiced.

How does this happen? The client may have a slow approval process for pay applications. The project manager may have been conservative in their billing percentages, not wanting to appear aggressive. The schedule of values may have back-loaded higher-value items, making early billing lag behind actual progress. Or the contractor may simply have fallen behind on billing — a surprisingly common issue when project managers are focused on field work rather than paperwork.

The result: the contractor has spent $200,000 but only collected $175,000. The $75,000 in underbilling represents cash that has been earned but not received, creating a gap that the contractor must fund out of pocket or through a line of credit.

Why Both Overbilling and Underbilling Are Dangerous

Contractors sometimes think of overbilling as a good thing — after all, more cash is better, right? And they view underbilling as merely an inconvenience that will sort itself out when the next pay application is approved. Both views are dangerously wrong.

The Danger of Overbilling

Overbilling creates an illusion of financial health. Cash is flowing in ahead of work performed, so the bank account looks strong. But that cash does not belong to the contractor — it belongs to the project. It must be used to fund the remaining work. When a chronically overbilled contractor uses that cash for other purposes — covering overhead, funding payroll on a different project, buying equipment, or taking distributions — they are spending money they have not earned.

Here is where it gets dangerous. If the overbilled project encounters cost overruns, the contractor has already collected the revenue but now needs more money to finish the work. They cannot bill ahead any further because they are already overbilled. They cannot slow down because the contract requires completion by a certain date. And they may not have the cash to fund the remaining work because they already spent the overbilling on something else.

This is the "profitable but broke" scenario that sinks construction companies. The project may still show a profit on paper, but the contractor does not have the cash to finish it. They start borrowing from one project to fund another, creating a cascading failure across their entire portfolio.

The Danger of Underbilling

Underbilling creates an immediate cash flow problem. The contractor has incurred costs — paid workers, bought materials, paid subcontractors — but has not collected the revenue to cover those costs. Every dollar of underbilling must be financed from somewhere, whether from the contractor's working capital, a line of credit, or by diverting cash from other projects.

A contractor who is underbilled by $200,000 across their active projects needs $200,000 in working capital just to stay even. If that working capital does not exist, the contractor starts paying vendors late, missing payroll, or delaying subcontractor payments. This damages relationships, triggers lien filings, and can spiral into insolvency.

Chronic underbilling also distorts financial statements. Revenue has been earned but not recognized through billing, which means the income statement may understate actual performance while the balance sheet carries a growing asset that depends entirely on the client paying when billed.

How Overbilling and Underbilling Appear on the WIP Schedule

The Work in Progress (WIP) schedule is the primary tool for identifying and monitoring overbilling and underbilling. A properly prepared WIP schedule compares three things for each active project:

1. Estimated completion percentage — based on costs incurred to date divided by the estimated total cost (cost-to-cost method)
2. Earned revenue — the completion percentage multiplied by the total contract value
3. Billings to date — the total amount invoiced to the client

The difference between earned revenue and billings to date reveals the billing position:

• If billings exceed earned revenue, the project is overbilled
• If earned revenue exceeds billings, the project is underbilled

A healthy WIP schedule shows most projects close to even, with minor overbillings and underbillings that offset each other. Red flags appear when the same projects are consistently overbilled by large amounts, when underbillings are growing month over month, or when the net position across all projects is significantly out of balance.

Your bonding company and bank review your WIP schedule carefully. Chronic overbilling tells them you may be spending tomorrow's money today. Chronic underbilling tells them you are not collecting for work performed. Either pattern raises concerns about your financial management and can affect your bonding capacity and credit terms.

The Balance Sheet Impact

Overbilling and underbilling do not just affect your cash flow — they directly impact your balance sheet, and your bonding company and bank scrutinize these numbers closely.

Overbilling Is a Liability

When you bill more than you have earned, the excess is classified as a current liability on your balance sheet, typically labeled "Billings in Excess of Costs and Estimated Earnings" or simply "Overbillings." This makes sense logically — you have received payment for work you have not yet performed. You owe that work to the client. Until you complete it, it is an obligation.

Large overbilling balances increase your total liabilities, weaken your current ratio, and can reduce your net worth on paper. Surety companies look at overbilling as a risk indicator. If your overbilling is large relative to your equity, they may question whether you can fund the remaining work on those contracts.

Underbilling Is an Asset

When you have earned more than you have billed, the excess is classified as a current asset on your balance sheet, typically labeled "Costs and Estimated Earnings in Excess of Billings" or simply "Underbillings." This also makes logical sense — the client owes you for work you have already performed. It is similar to accounts receivable, but it has not been invoiced yet.

However, underbillings are a softer asset than cash or receivables. The client has not agreed to a specific invoice amount. There may be disputes over completion percentages. And until a pay application is submitted and approved, the underbilling remains an internal accounting entry, not a legally enforceable claim.

Bonding companies view large underbillings with skepticism. They want to know why you are not billing for work completed. Is the client disputing progress? Is the project in trouble? Are you behind on pay applications? Persistent underbillings suggest operational or relationship problems.

How Overbilling Can Sink a Construction Company

The "profitable but broke" scenario deserves a deeper explanation because it is one of the most common ways construction companies fail.

Imagine a general contractor running five active projects. On three of them, the contractor is significantly overbilled — they have billed $2 million more than the work completed to date. That $2 million in cash looks great in the bank account. The owner uses some of it for a truck fleet upgrade, takes a large distribution, and covers overhead expenses that have been running higher than expected.

Then reality hits. Two of the overbilled projects encounter cost overruns — change orders that are not approved, subcontractor disputes, weather delays, and material price increases. The remaining work on those projects now costs more than originally estimated. The contractor needs to spend more to finish, but there is nothing left to bill because the billing is already ahead of the work. And the cash that was overbilled has already been spent.

Now the contractor is in a bind. They need cash to finish the overbilled projects but cannot generate it from those projects through billing. They start pulling cash from their underbilled projects — billing aggressively on jobs where they had been behind to generate cash for the projects that are bleeding money. This robbing-Peter-to-pay-Paul approach works for a while, but it makes every project's financial position worse.

Eventually, the contractor runs out of runway. Subcontractors file liens because they are not being paid. The bonding company discovers the billing discrepancies and pulls the contractor's bonding capacity. The bank calls the line of credit. What looked like a profitable operation six months ago is now insolvent.

This story plays out across the construction industry every year. It is preventable, but only with disciplined billing practices, accurate job costing, and regular WIP reporting.

Warning Signs Your Company Is Chronically Overbilled

Overbilling does not always mean you are in trouble — short-term overbilling can be a normal part of construction billing cycles. But chronic, large-scale overbilling is a warning sign. Watch for these indicators:

• Your cash balance feels higher than your margins justify. If you are running 8 percent net margins but always seem to have plenty of cash, you may be living on overbillings.
• The same projects are overbilled month after month. A project that is overbilled in month two and still overbilled in month eight has a billing problem that is not self-correcting.
• You are using project cash for non-project purposes. Buying equipment, taking distributions, or covering overhead with overbilled project cash is a red flag.
• Your WIP schedule shows most projects in an overbilled position. Some overbilling is normal. All projects overbilled is a pattern.
• You struggle to finish projects without pulling cash from other jobs. This is the clearest sign that overbilled cash has been spent elsewhere.
• Your bonding company or CPA has flagged overbilling on your financial review. If professionals who review construction financials are raising concerns, take them seriously.

Warning Signs Your Company Is Chronically Underbilled

Underbilling is less flashy than overbilling — it does not create the illusion of wealth — but it quietly drains cash and limits your ability to operate. Watch for these indicators:

• You are always short on cash despite having profitable projects. If the income statement shows profit but the bank account is empty, underbilling is a likely culprit.
• Pay applications are consistently submitted late or for amounts below actual progress. This is the most direct cause of underbilling and often stems from project managers who prioritize field work over billing.
• Clients routinely reduce your pay applications. If owners or GCs are cutting your billed amounts, you are falling further behind on collections.
• Your accounts receivable is low but your line of credit is maxed out. You are financing the gap between work completed and cash collected through debt.
• Retainage receivable is growing but collections are flat. Retainage is a form of underbilling. If you are not tracking it and collecting it at substantial completion, it accumulates.
• You rely on one project's billing to fund another project's costs. This cross-project dependency is a sign that your billing on individual projects is not keeping up with your spending.

How to Fix Billing Imbalances

Correcting overbilling and underbilling requires changes to both your billing practices and your financial monitoring processes. Here is a practical approach.

For Overbilling

• Stop front-loading billing schedules. Review your schedule of values to ensure billing percentages align with actual cost incurrence and work completion, not just what maximizes early cash.
• Segregate overbilled cash. Do not treat overbilled funds as available cash. Set aside overbilled amounts in a separate account or at minimum track them so you know how much of your cash balance is committed to future work.
• Update cost-to-complete estimates monthly. If costs are rising on an overbilled project, you need to know immediately so you can adjust your plan before the cash runs out.
• Review WIP monthly with project managers. Have a structured conversation about each project's billing position, anticipated costs, and remaining revenue. Do not let billing positions drift without explanation.
• Resist the temptation to spend overbilled cash. Owner distributions, equipment purchases, and overhead funded by overbilled project cash are borrowing from the future. Treat overbilled cash as belonging to the project until the work is complete.

For Underbilling

• Bill promptly and aggressively. Submit pay applications on time, every billing cycle, for the full amount of work completed. Do not leave money on the table out of politeness or inertia.
• Ensure your schedule of values reflects the actual cost distribution. If your early-phase work is cost-heavy, your schedule of values should reflect that so you are not systematically underbilling during the first half of the project.
• Track retainage and collect it at substantial completion. Retainage that sits uncollected for months after a project closes is an unnecessary drag on cash flow.
• Push back on pay application reductions. If clients are routinely cutting your billings, find out why and resolve the underlying issues — whether they involve documentation, quality disputes, or completion disagreements.
• Automate billing reminders. Use your project management or accounting system to flag when pay applications are due so billing never falls through the cracks.

The Role of Accurate Job Costing in Preventing Billing Issues

Overbilling and underbilling are fundamentally job costing problems. If you do not know exactly how much you have spent on a project and how much it will cost to complete, you cannot accurately assess whether your billing is ahead of or behind the work.

Accurate job costing provides the foundation for everything that follows:

• Percent complete calculations depend on actual costs to date and a reliable estimate of total costs. If your cost data is three weeks old or missing entire categories, your completion percentage is wrong — and your billing position analysis is based on bad data.
• Cost-to-complete estimates require knowing exactly where you stand on every cost code. If you do not track committed costs (open subcontracts and purchase orders), you may underestimate what remains to be spent, making an overbilled project look safer than it is.
• Margin analysis tells you whether the overbilling on a project is backed by sufficient remaining margin to complete the work. A project that is overbilled by $100,000 with $150,000 in remaining margin is in a very different position than one overbilled by $100,000 with only $50,000 in remaining margin.

Without solid bookkeeping that codes every cost to the correct job, your WIP schedule will be inaccurate and your billing position analysis will be unreliable. This is why construction-specific bookkeeping — not generic small business bookkeeping — is essential for contractors.

How WIP Reporting Catches Billing Problems Early

The WIP schedule is your early warning system for billing problems. When prepared monthly by someone who understands construction accounting, the WIP schedule reveals:

• Which projects are overbilled or underbilled and by how much
• Whether billing positions are improving or deteriorating by comparing current month to prior month
• The net company-wide billing position — total overbillings versus total underbillings across all active projects
• Fade or gain in estimated project margins — when estimated margins shrink on an overbilled project, cash flow risk increases
• Projects where the billing percentage and completion percentage diverge significantly — these warrant immediate investigation

A CFO-level review of your WIP schedule adds strategic context. Are your billing imbalances seasonal, related to specific project types, or driven by specific project managers? Are you trending toward a company-wide cash flow problem? Do you need to adjust your billing strategy, renegotiate payment terms, or increase your line of credit?

Contractors who do not prepare WIP schedules are flying blind on their billing positions. They may not realize they are overbilled until the cash runs out, or underbilled until they cannot make payroll. Monthly WIP reporting transforms billing management from reactive crisis management to proactive financial control.

How FinTruction Monitors Billing Positions for Contractors

At FinTruction, we build billing position monitoring into every client engagement. Our approach covers the entire financial pipeline:

Our construction bookkeeping team ensures that every cost is coded to the correct job and cost category in real time. This gives us the clean, current cost data that accurate billing position analysis requires. Without reliable bookkeeping, WIP schedules and billing analyses are built on a flawed foundation.

Our controller services produce monthly WIP schedules that compare earned revenue to billings on every active project. We flag overbilled and underbilled projects, track trends month over month, and work with project managers to reconcile billing positions. When a project's billing gets out of alignment, we identify it early — before it becomes a cash flow crisis.

Our CFO services provide strategic oversight of your company's overall billing position. We analyze company-wide net overbilling and underbilling, assess the impact on working capital and bonding capacity, and recommend adjustments to billing practices, payment terms, and cash management strategies.

We also integrate with your project management and accounting systems to streamline data flow. When field data, billing, and accounting are connected, billing position analysis happens faster and with fewer errors.

If you are a contractor who does not know your billing position across active projects — or worse, if you know it and the numbers are concerning — we can help you get control of it.

Worried About Your Billing Position?

Schedule a Free Consultation

Frequently Asked Questions About Overbilling and Underbilling

Is overbilling in construction illegal or unethical?

Intentional overbilling — such as falsifying completion percentages or inflating the schedule of values to collect payment for work not performed — can constitute fraud and is both illegal and unethical. However, most overbilling in construction is a natural result of billing cycles, schedule-of-values weighting, and the timing difference between when costs are incurred and when work is billed. Moderate, short-term overbilling is a normal part of construction accounting. The problem arises when overbilling is chronic, excessive, or the overbilled cash is spent on non-project purposes.

How do overbilling and underbilling affect my bonding capacity?

Surety companies review your WIP schedule as part of every bonding evaluation. Large or chronic overbilling tells them you may be spending project cash before earning it, which increases their risk. Large underbillings tell them you are not collecting for work performed, which weakens your cash position. Both conditions can reduce the bonding capacity a surety is willing to extend. Maintaining balanced billing positions across your portfolio demonstrates financial discipline and supports stronger bonding relationships.

Can a project be both overbilled and underbilled at different times?

Yes, and this is common. A project might be underbilled in the early months when mobilization costs are high but billing has not started, then shift to overbilled in the middle months as billing catches up and pulls ahead, and then return to even or underbilled at closeout when remaining work exceeds remaining billable revenue. The billing position fluctuates throughout the life of a project. What matters is that you track these fluctuations and manage them intentionally rather than discovering them after the fact.

What is an acceptable level of overbilling or underbilling?

There is no single threshold, but most construction accountants and surety professionals consider overbilling or underbilling within 5 to 10 percent of the contract value to be within a normal range. When overbilling exceeds 15 to 20 percent of the contract, it warrants close monitoring. When it exceeds 25 percent, it typically indicates a structural problem with the billing approach or the project's cost trajectory. The key metric is whether the remaining margin on the project is sufficient to cover the remaining work — if it is, moderate overbilling is manageable. If it is not, the contractor is heading for a cash crisis.

How often should I review my billing positions?

Monthly, at minimum. Your WIP schedule should be prepared at the end of every month and reviewed by the project management team and financial leadership. For contractors with large or complex projects, a mid-month check on billing positions can catch problems even earlier. The review should compare current billing positions to prior month, identify projects where the position is deteriorating, and trigger action plans for any project where overbilling or underbilling exceeds acceptable thresholds.