Overbilling and Underbilling: What Every Contractor Must Understand

Understanding the difference between what you've billed and what you've earned is fundamental to construction finance. Get it wrong and you'll mislead yourself, your bank, and your surety.

Understanding your billing position protects cash flow and relationships

Last Updated: February 2026|11 min read

In construction accounting, what you bill and what you earn are two different things. Overbilling and underbilling measure the gap between them—and that gap matters enormously for your cash flow, balance sheet, and relationships with banks and sureties.

As covered in our Job Costing Guide for Contractors, proper WIP reporting is the foundation of construction finance. This article digs deeper into one of the most misunderstood aspects: the over/under billing position.

Why This Matters

Your over/under billing position tells you whether you're financing your customers (underbilled) or they're financing you (overbilled). It affects your working capital, bonding capacity, and ability to take on new work. Every contractor needs to understand this.

Billing Position Impact

Overbilling

Cash positive

Underbilling

Cash negative

Working Capital

Asset vs liability

Bank Relations

Credit impact

Definitions and Calculation

To understand overbilling and underbilling, you first need to understand earned revenue versus billed revenue.

Key Terms

Earned Revenue

Revenue recognized based on percentage of completion. If a job is 40% complete, you've earned 40% of the contract value—regardless of what you've billed.

Billed Revenue (Billings to Date)

The total amount you've invoiced to the customer. This is what shows on your progress billings or pay applications.

Over/Under Billing

The difference between earned revenue and billed revenue.

The Calculation

Over/Under Billing = Billed Revenue - Earned Revenue

Positive result (Billed > Earned) = Overbilled
Negative result (Billed < Earned) = Underbilled

Overbilled

Also called "Billings in Excess of Costs and Estimated Earnings"

You've billed more than you've earned. You have the customer's money for work not yet performed.

Underbilled

Also called "Costs and Estimated Earnings in Excess of Billings"

You've earned more than you've billed. You've effectively loaned money to your customer.

Worked Example

Project: $1,000,000 contract
Estimated Total Cost: $800,000
Costs Incurred to Date: $320,000
Billed to Date: $450,000

% Complete: $320,000 / $800,000 = 40%

Earned Revenue: $1,000,000 x 40% = $400,000

Over/Under: $450,000 - $400,000 = $50,000 Overbilled

You've billed $50,000 more than you've earned. This is favorable for cash flow.

Balance Sheet Presentation

Overbillings and underbillings appear on your balance sheet—but on opposite sides. Understanding where they show up helps you understand what they really mean.

Overbillings = Liability

Shows as a current liability on your balance sheet.

Why? You've collected money for work you haven't performed yet. You owe that work to your customer. It's similar to deferred revenue.

Underbillings = Asset

Shows as a current asset on your balance sheet.

Why? You've earned revenue you haven't billed yet. It's money your customer owes you, similar to accounts receivable.

The Counterintuitive Part

Having a liability (overbilled) is actually good for your cash position, while having an asset (underbilled) is bad for cash. This confuses many contractors who think assets are always good and liabilities are always bad. In construction, overbilling creates working capital; underbilling consumes it.

How It Flows Through Financial Statements

Statement	Overbilled Impact	Underbilled Impact
Balance Sheet	Current liability increases	Current asset increases
Working Capital	Decreases (more liabilities)	Increases (more assets)
Cash Position	Higher (collected ahead)	Lower (financing customer)
Income Statement	No direct impact*	No direct impact*

*Revenue on the income statement is based on earned revenue, not billings. Over/under billing is a balance sheet phenomenon.

Why Banks Care About Your Over/Under Position

When you apply for a line of credit or term loan, your bank analyzes your WIP schedule carefully. Your over/under billing position tells them important things about your business.

Working Capital Quality

Banks scrutinize whether your working capital is "real." Large underbillings inflate your current assets, making working capital look better than it is. Bankers often adjust working capital calculations to exclude or discount underbillings.

Collection Risk

Underbillings represent work you've done but haven't billed. Can you collect? If there are disputes, change orders, or customer payment issues, those underbillings may never convert to cash. Banks see large underbillings as potential bad debt.

Cash Flow Management

Consistent overbilling suggests good cash management and billing discipline. Consistent underbilling suggests you're not keeping up with documentation, have billing disputes, or are taking on more work than you can finance.

Borrowing Base Impact

If you have a borrowing base formula (common for contractor lines of credit), underbillings may be excluded or have a lower advance rate than regular receivables. Banks view underbillings as less collectible than invoiced amounts.

Cash Flow Implications

The cash flow impact of overbilling versus underbilling is straightforward but critical to understand.

Overbilling = Cash Positive

Customer is financing your work
Reduces need for working capital
Frees cash for other projects or operations
Acts like an interest-free loan from your customer

Underbilling = Cash Negative

You are financing your customer's project
Consumes working capital
Requires borrowing or using cash reserves
You're giving an interest-free loan to your customer

The Working Capital Math

Consider two contractors, each with $10M in backlog:

Contractor A: Net Overbilled $500K

Has $500K more cash than if billing matched earnings. This cash funds payroll, materials, equipment—reducing borrowing needs.

Contractor B: Net Underbilled $500K

Has $500K less cash than if billing matched earnings. Must borrow or use reserves to fund the gap, paying interest and reducing capacity.

When Overbilling Is Good (And When It's a Problem)

Overbilling is generally favorable, but context matters. Understanding when it's healthy versus a warning sign helps you manage your business better.

When Overbilling Is Good

Front-Loaded Billing by Design

You negotiated a schedule of values that bills higher percentages early in the project (mobilization, site work, early phases). This is smart cash management, not manipulation.

Matching Payment Terms

If you pay suppliers and subs net 30 but collect from owners net 45-60, overbilling offsets the timing gap. You're using customer funds to bridge the payment cycle.

Consistent, Moderate Levels

Contractors who are consistently 5-15% overbilled across their portfolio are demonstrating good billing practices. The position is stable and reflects operational discipline.

When Overbilling Is a Warning Sign

Excessive Front-Loading

If you're 50%+ overbilled on a job, you've collected most of the contract value before doing most of the work. You'll have negative cash flow as the job progresses. This is unsustainable and creates back-end problems.

Masking Cost Overruns

Sometimes contractors maintain overbilling by not updating cost-to-complete estimates. The project looks overbilled, but actual costs are running ahead. When the true costs hit, the overbilling disappears—along with the profit.

Aggressive Revenue Recognition

If your overbilling depends on optimistic percentage-complete calculations or cost-to-complete estimates that keep slipping, you're not really overbilled— you're just delaying the recognition of problems.

The Overbilling Trap

Some contractors become dependent on overbilling to fund operations. They need to maintain aggressive front-loading just to make payroll. If they lose a project or a customer tightens billing requirements, they face a cash crisis. Sustainable overbilling supplements working capital; it doesn't replace it.

Industry Norms and Benchmarks

What constitutes a healthy over/under billing position varies by contractor type, project mix, and customer base. Here are general guidelines.

Contractor Type	Typical Range	Notes
General Contractors	5-15% overbilled	GCs often control billing schedules
Specialty Trades	0-10% overbilled	Less control over billing to GC
Heavy/Civil	5-20% overbilled	Mobilization-heavy, public work
Design-Build	Varies widely	Design phases often underbilled

Surety Expectations

Sureties view over/under billing through a risk lens. Their general preferences:

Prefer net overbilled or balanced: Demonstrates billing discipline and cash management
Concerned by large underbillings: Questions collectibility and management competence
Watch for trends: A contractor moving from overbilled to underbilled over time signals deterioration
Project-level review: One heavily underbilled project may indicate a problem even if overall position looks okay

Best Practices for Managing Your Position

Operational Recommendations

Negotiate favorable schedules of values that allow front-loading
Bill promptly—delays turn potential overbilling into underbilling
Document change orders quickly to support billing
Review WIP monthly and address underbilled projects immediately
Maintain target overbilling levels as part of cash flow management
Don't let overbilling become a crutch for inadequate working capital

Construction Financial Expertise

Eagle Rock CFO helps contractors manage WIP, optimize billing positions, and build the financial infrastructure that supports growth and bonding capacity.

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