Over and under billing in construction is the difference between what a contractor has invoiced an owner and what that contractor has earned based on work completed to date — overbilling means you've billed more than you've earned; underbilling means you've earned more than you've billed. This isn't an accounting technicality. It's the difference between a job that's funding your business and one that's quietly draining it.
Key takeaways
Overbilling defined: Overbilling — also called billings in excess of costs — occurs when a contractor invoices an owner for more than the percentage-of-completion method says has been earned, and it is recorded as a current liability on the balance sheet.
Underbilling defined: Underbilling — also called costs in excess of billings — occurs when a contractor has performed work and incurred costs but hasn't yet invoiced for them, creating a current asset on the balance sheet and meaning the contractor is effectively financing the owner's project.
The formula: Over/under billing equals total billings to date minus earned revenue to date, where earned revenue is calculated using the percentage-of-completion method.
The cash-flow risk: Overbilling creates a deceptive cash position — cash collected early must be offset by future work performed, and surety underwriters treat persistent overbilling as a sign of poor job cost management.
The visibility gap: QuickBooks Online does not calculate or surface over/under billing natively — a WIP layer is required to see your position at the job level.
What is over and under billing in construction?
Over and under billing in construction describes the gap between a contractor's progress billings and the revenue that contractor has legitimately earned based on actual work completed. The two terms represent opposite conditions with opposite balance sheet treatments, and both have real consequences for cash flow, bonding capacity, and job profitability.
Overbilling defined (billings in excess of costs)
Overbilling occurs when a contractor invoices the owner for more than the percentage-of-completion method says has been earned at that point in the job. If you're 40% done with a $1,000,000 contract but you've billed $500,000, you've billed $100,000 more than your earned revenue of $400,000. That $100,000 is a liability — you owe the owner future performance to justify what you've already collected.
The most common cause is front-loading, also called advance billing, where contractors weight early billings heavily to improve early-stage cash flow. While this improves liquidity in the short term, it creates an obligation that has to be worked off later in the job, often when costs are at their highest.
Underbilling defined (costs in excess of billings)
Underbilling occurs when a contractor has incurred costs and performed work but hasn't invoiced for it yet. Using the same $1,000,000 contract example: if you're 60% complete but have only billed $400,000, you've earned $600,000 in revenue but are $200,000 behind on billings. That $200,000 gap is a current asset on your balance sheet — work done but not yet collected. In plain terms, underbilling means you're financing the project owner with your own working capital.
How do you calculate over and under billing on a construction job?
The over/under billing formula is: Over/Under Billing = Total Billings to Date − Earned Revenue to Date, where a positive result means you're underbilled and a negative result means you're overbilled. The calculation depends on the percentage-of-completion method to establish earned revenue — without a completion percentage, there's no benchmark to compare billings against.
Here are the three calculation steps:
Calculate percent complete: Costs Incurred to Date ÷ Total Estimated Costs. This gives you the proportion of the job that's been completed based on cost input.
Calculate earned revenue to date: Percent Complete × Contract Price. This is the revenue the contractor has legitimately recognized under the percentage-of-completion method.
Calculate over/under billing: Total Billings to Date − Earned Revenue to Date. A positive result means you're underbilled (you've earned more than you've collected). A negative result means you're overbilled (you've collected more than you've earned).
Here's a worked example using a $1,000,000 contract. Say you've incurred $400,000 in costs against a $600,000 total estimated cost budget, and you've billed $700,000 to date.
Percent complete: $400,000 ÷ $600,000 = 66.7%
Earned revenue to date: 66.7% × $1,000,000 = $667,000
Over/under billing: $700,000 − $667,000 = −$33,000 (overbilled by $33,000)
This calculation is exactly what a WIP schedule surfaces at the job level. The WIP schedule — short for work-in-progress schedule — is the report that brings all active jobs together in one view so you can see your total overbilled and underbilled exposure across the portfolio at once. For a step-by-step guide to building one, see how to build a WIP schedule in QuickBooks Online.
The table below summarizes the key differences between overbilled and underbilled status across the five attributes that matter most to controllers, lenders, and surety underwriters.
What is the percentage-of-completion method?
The percentage-of-completion method — also called PCM — is the standard construction revenue recognition approach under ASC 606, where revenue is recognized proportionally as work is completed rather than all at once at project end. Under PCM, a contractor recognizes revenue equal to the contract price multiplied by the percentage of the job complete — not based on how much has been billed or collected.
PCM is the accounting standard that makes over/under billing calculations meaningful. Without it, there's no "earned revenue" figure to compare against billings, and the over/under position is invisible. Contractors who track costs by job — but skip the completion-percentage step — are essentially operating blind on job-level billing health.
How does over and under billing appear on the balance sheet?
Overbilling (billings in excess of costs) is classified as a current liability on the balance sheet; underbilling (costs in excess of billings) is classified as a current asset. Both classifications follow directly from the percentage-of-completion method under GAAP accounting standards and are required disclosures for contractors reporting under ASC 606.
For lenders and bonding companies, these line items aren't formalities. Surety underwriters read the balance sheet specifically for the billings in excess and costs in excess line items as part of their prequalification review. A contractor carrying large underbillings relative to equity triggers scrutiny — it signals the company has absorbed labor and material costs on active jobs without recovering that cash through billings, which raises questions about whether the business has the working capital to complete jobs already underway.
The underbillings-to-equity ratio — which measures total underbilled amounts as a percentage of total equity — is a metric surety underwriters use to assess financial risk. A high ratio tells the underwriter that a contractor's apparent equity is partially supported by uncollected earned revenue, not realized cash. For contractors pursuing bonding on larger projects, keeping this ratio in check is as important as maintaining a clean credit history. For a more detailed look at how these balance sheet dynamics affect homebuilders specifically, see WIP reporting for homebuilders.
Why is overbilling a cash-flow trap in construction?
Overbilling feels like strong cash flow, but it means you've collected money you haven't yet earned — and when the job progresses, that gap has to close through future work, not future billing. The cash has come in, but the obligation to perform remains.
Here's the mechanics of the trap using the earlier example: you collected $700,000 but only earned $667,000 at this point in the job. The next $33,000 of work you complete earns you nothing new in cash — you're working it off. If your cost burn during that period is heavy, you're consuming cash to perform work you've already been paid for, without any new cash coming in. That's the window where job borrow — the practice of using cash collected early on one job to cover costs on another — creates a hidden liability that only surfaces when both jobs advance simultaneously.
Surety underwriters treat persistent overbilling as a warning sign, not just a timing difference. A contractor who routinely front-loads billings to improve early cash flow is, in effect, borrowing from future periods. If a job runs over budget or falls behind schedule, the overbilled position compounds the problem — you've already collected the cash, and now you need more money to complete the work. For a deeper look at how billing position connects to construction billing cash flow, the pattern repeats across job types and contract structures.
How underbilling creates its own cash risk
Underbilling is often treated as the "safer" billing position, but carrying large underbillings strains working capital in a direct way: the contractor has absorbed labor and material costs without recovering them through billings. Your crews are paid, your suppliers are paid, and your bank account reflects all of that outflow — but the corresponding inflow hasn't arrived yet.
This situation is common on jobs with delayed invoicing cycles, milestone-based billing structures, or undocumented change orders where additional work has been performed but hasn't been formally approved or billed. The longer the billing lag, the more the contractor is effectively extending credit to the project owner at the contractor's own expense. A controller managing multiple active jobs can quickly find that the aggregate underbilled position across the portfolio is consuming a significant share of available working capital.
What causes over and under billing on construction jobs?
Over and under billing on construction jobs trace back to a predictable set of root causes, most of which are invisible in general-ledger accounting alone — they only surface when job-level WIP tracking is in place.
Advance billing / front-loading: Contractors intentionally bill early to front-load cash flow, creating an overbilled position from the start of the job.
Undocumented change orders: Work gets performed outside the original contract scope, costs are incurred, but the change order hasn't been formally approved or billed — creating underbilling.
Delayed invoicing: Billing cycles that don't match the pace of work — monthly invoicing on a fast-moving job — create chronic underbilling gaps.
Cost estimate errors: If the original budget underestimates total project cost, the completion percentage is artificially inflated, making the job appear more overbilled than it is.
Missing cost accruals at month-end: Costs incurred but not yet posted to the GL — subcontractor invoices in transit, materials received but not billed — understate costs to date and distort the completion percentage.
Multi-job allocation errors: Costs coded to the wrong job inflate one job's cost-to-date while understating another's, throwing off the completion percentage for both.
All six causes are invisible if you're only looking at the GL. A P&L by job tells you revenue and cost, but it doesn't tell you whether those numbers are in the right proportion for where the job actually stands. For a practical walkthrough of setting up job-level tracking, see how to build a WIP schedule in QuickBooks Online.
Why can't QuickBooks Online show your over/under billing position?
QuickBooks Online does not have a native WIP schedule or over/under billing report — it records transactions, not job completion percentages. QBO tracks what was billed and what costs were incurred, but it has no field for "percent complete" or "estimated total cost at completion." Without those two data points, there's no way to calculate earned revenue to date inside QBO, and no over/under billing position to report.
One finance manager described the problem directly: "It would be nice if this was something that would update automatically. Like if it tied into QuickBooks as it is, that would be so great because then we would get the visibility into it all the time." That visibility gap is structural — QBO was built for general small business bookkeeping, not job cost accounting. The limitation isn't a missing setting; it's a fundamental architectural difference.
Contractors using QBO for construction accounting typically handle this by exporting cost and billing data to a spreadsheet, manually entering estimated total costs and completion percentages for each job, and calculating the over/under figure outside the system. According to LiveFlow's Finance in the AI Era report (May 2026), 78% of finance teams still move data primarily via manual spreadsheet exports — a workflow that's error-prone and always reflects a historical snapshot, not the current job status. By the time you've finished building the spreadsheet, the numbers have already moved. If you're starting from QBO and want to build this layer manually, see how to build a WIP schedule in QuickBooks Online for a step-by-step approach.
How do you get live over/under billing visibility across all your jobs?
A live WIP solution calculates earned revenue and over/under position continuously at the job level, rather than as a monthly manual export from your accounting system. The difference isn't incremental — it changes close from a data-gathering exercise into a verification step.
Flow ERP, LiveFlow's AI-native ERP purpose-built for multi-entity construction businesses, addresses exactly this gap. Flow is built for contractors running multiple jobs, locations, or subsidiaries — where the over/under position needs to be visible across all active jobs in a single consolidated view, not reconstructed from separate spreadsheets each month. For contractors managing multiple entities that share labor or equipment, the consolidated WIP view matters as much as the individual job view, because intercompany cost allocations affect every job's completion percentage.
Flow's AI Month-End Close Agent runs a dynamic checklist tied to actual data, which means close becomes a sanity check rather than a 15-day project. Bank reconciliation runs continuously via Plaid — the financial data network — rather than as a month-end batch, so close starts mostly reconciled. For controllers who currently spend the first week of every close just gathering data, that continuous-close architecture changes what's possible. For homebuilders specifically, who face balance-sheet scrutiny from construction lenders on the costs-in-excess line, see WIP reporting for homebuilders for a more targeted treatment.
What to look for in a WIP and billing tool for construction
When evaluating a WIP solution, look for these specific capabilities:
Job-level over/under calculation tied to live cost data: The system pulls actual costs from the GL in real time, not from a periodic export. Any cost posted to a job should update the completion percentage immediately.
Balance-sheet auto-classification: Billings in excess should post as a current liability automatically; costs in excess should post as a current asset. No manual journal entries required.
Multi-entity consolidated view: Contractors with subsidiaries, joint ventures, or multiple operating entities need to see aggregate over/under exposure across all entities in a single report — not just job-by-job.
Integration with existing accounting data: The WIP layer should pull from the same GL that drives your financial statements, so there's one version of costs and billings — not two systems that need to be reconciled.
Continuous reconciliation rather than month-end batch updates: Flow ERP's bank reconciliation runs continuously via Plaid, so the WIP data reflects current cash position, not last month's close. The AI Month-End Close Agent runs a dynamic checklist tied to actual data, so the close process is a verification step, not a data-gathering sprint.
Account Harmonization across entities: Account Harmonization is the process of standardizing chart of accounts naming conventions across entities so consolidated WIP reporting is accurate. Flow ERP handles this using AI on the way in, eliminating the mapping errors that corrupt multi-entity WIP data.
Audit-ready documentation: Every entry in the WIP schedule should trace back to source transactions in the GL, so there's no gap between what the WIP report shows and what the general ledger supports.
See your over/under billing position in real time
Knowing your over/under billing position on every active job, in real time, is the difference between managing cash and reacting to it. If you're currently running this analysis in a spreadsheet that gets updated once a month — or once a quarter before a bonding review — you're making cash and project decisions based on data that's already out of date.
Most contractors start in the same place: a QBO export, a manually built WIP tab, and a close cycle that takes longer than it should. Flow ERP is built to replace that workflow with a live, job-level WIP view that's connected to your actual GL data across all entities. The AI agents handle the routine work — reconciliations, journal entries, close checklists — so your team can focus on the numbers that actually require judgment.
Book a demo to see how Flow ERP surfaces over/under billing across your entire job portfolio in real time.
Frequently asked questions
What is over/under billing in construction?
Over and under billing in construction describes the difference between a contractor's total billings to date and the revenue that contractor has earned based on actual work completed, calculated using the percentage-of-completion method. Overbilling — recorded as a current liability called billings in excess of costs — means the contractor has invoiced more than it has earned. Underbilling — recorded as a current asset called costs in excess of billings — means the contractor has performed work but hasn't yet invoiced for it. Both conditions have direct consequences for cash flow, bonding capacity, and financial statement presentation.
How do you calculate over and under billing?
Over/under billing equals total billings to date minus earned revenue to date, where earned revenue equals percent complete multiplied by the contract price, and percent complete equals costs incurred to date divided by total estimated costs. For example, on a $1,000,000 contract where $400,000 in costs have been incurred against a $600,000 total estimated cost budget and $700,000 has been billed: percent complete is 66.7%, earned revenue is $667,000, and the over/under position is −$33,000 (overbilled). A positive result means underbilled; a negative result means overbilled. Flow ERP surfaces this calculation at the job level in real time, without a manual spreadsheet step.
Why does overbilling hurt cash flow?
Overbilling creates a deceptive cash position: you've collected cash that represents future work obligations, not completed performance. When the job advances, the contractor must deliver the remaining work without receiving additional cash — because the billing has already been issued. Persistent overbilling also triggers scrutiny from surety underwriters, who treat it as evidence of front-loaded billing practices or underlying job cost management problems, which can restrict bonding capacity on future projects.
Can QuickBooks Online produce an over/under billing report?
QuickBooks Online cannot produce a native over/under billing or WIP schedule report because it has no field for estimated total cost at completion or job completion percentage — the two inputs required to calculate earned revenue under the percentage-of-completion method. Contractors using QBO for construction accounting typically build a manual WIP spreadsheet outside the system, which is error-prone and always reflects a historical snapshot. Flow ERP is purpose-built for construction job cost accounting and surfaces over/under billing at the job level tied to live GL data, without a separate spreadsheet step.
Is it better to be overbilled or underbilled?
Neither overbilling nor underbilling is categorically better — both signal a misalignment between billings and earned value that requires management. Overbilling provides short-term cash but creates a future performance obligation and raises flags with surety underwriters. Underbilling means work has been performed without recovery, straining working capital and — if underbillings are large relative to equity — signaling potential financial risk to lenders and bonding companies. The goal is a balanced WIP position where billings track closely with earned value across the job lifecycle.
