Construction Accounting: A Contractor’s Guide to the Numbers

Construction accounting is its own discipline, and not in a vague “every industry is special” way. The financial questions a contractor faces are structurally different from those facing a retail business or a professional services firm. The combination of long-term contract revenue recognition, job-level cost tracking, retainage, equipment-heavy depreciation, and a labor force that often mixes employees and subcontractors creates an environment where standard bookkeeping is genuinely insufficient.

Start with revenue recognition. In most businesses, income is recognized when a sale is made or a service is delivered. Construction accounting does not work that way for multi-month or multi-year projects. A contractor who signs a $4 million contract in January does not recognize $4 million in January. They recognize revenue over the life of the project as work is performed, using either the percentage-of-completion method or the completed-contract method under IRC §460. The choice between these methods has direct tax consequences, and the IRS mandates percentage-of-completion for most contractors above the small-contractor threshold. Getting this wrong does not just affect how your financial statements look. It determines when you pay tax.

Then there is job costing. Construction accounting requires tracking costs at the individual project level, not just in aggregate. Direct materials, direct labor, subcontractor invoices, equipment costs, and allocated overhead all need to be assigned to specific contracts. This is not standard bookkeeping. Most general-purpose accounting software is not set up for project-level job costing out of the box, and a bookkeeper without construction experience will often miscategorize costs in ways that make job-level profitability invisible. You end up not knowing which contracts made money and which did not, which is the opposite of what you need to manage a construction business.

Retainage creates complexity that does not exist in other industries. On most construction contracts, the project owner or general contractor withholds a percentage of each draw, typically 5% or 10%, until substantial completion. On a $4 million job at 10%, that is $400,000 sitting on your balance sheet as a receivable you have not collected. How you account for it affects your cash flow projections, tax liability, and the financial statements that bonding companies and lenders scrutinize. Surety companies look at retainage receivables carefully when evaluating construction businesses, and if your books do not handle retainage clearly, your balance sheet may not reflect your actual financial position.

Sales tax on materials is another challenge most industries never face. Most states charge sales tax on tangible personal property, including construction materials, but the application is nuanced. Materials that become permanent parts of real property under a qualifying capital improvement contract may be treated differently from materials used for repair and maintenance, and the distinction turns on facts that change project by project. State revenue departments audit construction companies for sales tax compliance more aggressively than most other industries, and the assessments can reach back years. IRS Publication 334 covers the federal small-business framework, but the sales tax piece is governed by your state.

Insurance accounting adds yet another layer. Workers’ compensation premiums in construction are calculated based on payroll by job classification. Ironworkers carry dramatically different rates than office staff, and final premiums are adjusted at year-end based on an audit of actual payroll. If your books do not accurately track payroll by classification, your workers’ comp audit will use incorrect data, typically resulting in overpayment. Most states also require disability or unemployment coverage that creates ongoing accounting and reporting obligations at the per-employee level. The dollar stakes are real: a $1,000,000 payroll classified as carpentry at, say, a $12 rate per $100 of payroll costs $120,000 in workers’ comp premium, while the same dollars sitting in a roofing or steel-erection class can run several times that. Misclassifying field hours into the wrong code, or failing to split a working owner’s time between office and field, produces an audit adjustment that lands as a lump-sum premium bill long after the cash from those jobs is gone.

Equipment and depreciation are a major area in their own right. Construction companies buy and depreciate significant equipment, and under IRS Publication 946, IRC §179 allows immediate expensing of qualifying equipment while bonus depreciation under §168(k) provides additional first-year deductions. The interaction of these elections with the PCM method, particularly the look-back rules under §460(b), requires careful planning. Taking aggressive depreciation in a year with strong PCM revenue is different from taking it in a loss year, and these decisions compound over time.

Entity structure matters more in construction than in many industries because of the self-employment tax exposure on lumpy, high-dollar income. A sole proprietor or single-member LLC reports income on Schedule C and pays self-employment tax under the rules in the Schedule C instructions. An S corporation election can reduce that exposure, but the reasonable-compensation requirement applies and the IRS watches construction owner salaries closely. Our S-corp election guide walks through the trade-off.

All of this adds up to an accounting function that requires genuine construction-industry experience. Construction accounting done properly is a specialty, not a generalist service. A general bookkeeper can reconcile your bank account. They typically cannot set up a proper job cost system, handle retainage correctly, prepare certified payroll, apply construction sales tax rules, or advise on entity structure. Our team provides construction accounting and tax services to contractors nationwide. Reach us through the new client inquiry form to talk through your situation.

The percentage-of-completion method, or PCM, is the revenue recognition approach most construction contractors use for long-term contracts, and for contractors above a certain size it is not a choice. Under IRC §460, contractors working on contracts that span more than one tax year are generally required to use PCM unless they qualify for the small-contractor exception. Understanding how PCM works is not just a financial reporting question. It determines when you pay tax on income that may not yet be in your bank account.

The core mechanics are straightforward: you recognize revenue in proportion to how much of the contract you have completed in a given tax year. If you have a $2 million contract and have completed 40% of the work by December 31, you recognize $800,000 of revenue for that year, regardless of how much you have actually billed or collected. This matches the economic reality of long-term project work better than either cash accounting, which recognizes income only when cash arrives, or the completed-contract method, which defers everything until the job is done. IRS guidance on long-term contracts provides the administrative detail on how completion is measured.

Measuring the completion percentage is where construction accounting gets operationally complex. The most widely used approach is the cost-to-cost method: divide the costs incurred to date by the total estimated costs for the contract, and the resulting fraction is the completion percentage. Apply that fraction to the total contract price and you have your recognized revenue. If a job has estimated total costs of $1.5 million and you have incurred $600,000 so far, you are 40% complete, so on a $2 million contract you recognize $800,000 of revenue for the period.

This creates a direct dependency on accurate, current cost estimates. Your revenue recognition figure is only as reliable as your estimate of total contract costs. If you underestimate remaining costs, your completion percentage is overstated, you recognize more revenue than you should in the current year, and you pay tax on income that will be offset by costs you have not incurred yet. If you overestimate remaining costs, you defer income into future years, which the IRS views skeptically when the pattern persists across multiple contracts. The integrity of your cost estimates is not just a project management issue. It is a tax compliance issue with IRS exposure attached.

The look-back rule under §460(b) adds a compliance obligation that many contractors either do not know about or mishandle. When a long-term contract is completed, you must file Form 8697 and perform a look-back calculation comparing what you actually reported under PCM each year with what you should have reported based on actual completion. If you over-reported income in prior years because actual costs came in higher than estimated, the IRS owes you interest. If you under-reported because actual costs were lower, you owe interest to the IRS. This interest is computed at the underpayment rate, and missing the filing is a compliance error that attracts IRS attention, particularly for contractors with multiple large contracts completing in the same year.

Change orders complicate PCM in ways most accounting systems do not handle automatically. When a change order adds scope, and therefore adds to the total contract value and total estimated costs, you need to update both your revenue recognition calculation and your cost-to-complete estimate. Approved change orders are generally incorporated into the original contract for PCM purposes. Disputed change orders, where the additional compensation has not been agreed to by the owner, require different treatment. IRS Publication 538 provides relevant context on how contingent contract items affect revenue recognition.

For contractors who qualify for the small-contractor exception, the completed-contract method (CCM) is available and may be preferable in some situations. Under CCM, no revenue or cost is recognized on a contract until it is complete, which can create significant income bunching if several large contracts finish in the same year, or meaningful deferral during years when work is actively ongoing. The planning question is whether the CCM’s deferral benefit outweighs the lumpiness it creates and the bracket implications in completion years. The qualifying threshold is indexed annually, set at $31 million for 2025 under Rev. Proc. 2024-40.

From a practical standpoint, PCM compliance requires a job cost accounting system that produces reliable cost-to-date figures by contract on a period-by-period basis. Construction-specific platforms built for this purpose track committed costs, change orders, and cost-to-complete in one place. A generic accounting setup, without contractor-specific configuration, typically cannot produce the job-level cost reports needed to support accurate PCM. If your year-end tax preparation involves reconstructing job cost data that was not tracked in real time, your PCM numbers are estimates at best.

Getting PCM right also matters for bonding and lending. Surety companies require CPA-prepared financial statements that reflect proper revenue recognition, and banks evaluating your credit look at the same statements. A contractor whose financials reflect consistent, accurate PCM presents a far more credible picture than one whose numbers fluctuate in ways that cannot be explained by contract activity. Our team handles construction accounting for general contractors and specialty trades. Reach us through the new client inquiry form to discuss your specific situation, or see our corporate returns service for the filing side.

Sales tax on construction is one of the most misunderstood areas of construction accounting, and state revenue departments do not accept “we didn’t know” as a defense during an audit. The rules vary by state, but the underlying framework is similar enough that every contractor needs to understand the moving parts: what is taxable, who is treated as the consumer, and how contract structure changes the answer.

The baseline rule in most states is that building materials and supplies are subject to sales tax when purchased, and the contractor is treated as the end consumer of those materials. This is true whether you are buying concrete, lumber, PVC pipe, or HVAC equipment that will be permanently installed. The purchase triggers the tax. What generally does not trigger sales tax in most states is the labor itself. Many states do not impose sales tax on labor for the improvement of real property, and in a labor-intensive project that exemption limits the taxable portion substantially. Your state’s revenue department publishes the specific treatment, and construction guidance often runs to dozens of documents. Because the materials cost itself is a deductible business expense regardless of how the sales tax is handled, it is worth reading the framework in IRS Publication 535 on business expenses alongside your state’s rules.

Where construction accounting gets complicated is in how contract types interact with these rules. Under a lump-sum contract, a fixed price for the complete job, the contractor is generally treated as the consumer of all materials used. The contractor pays sales tax when purchasing those materials, and the total contract price billed to the client is not subject to further sales tax. The client pays one price and the tax was already absorbed. Under a time-and-materials contract, the contractor charges the client separately for materials and labor, and the contractor may be required to collect sales tax from the client on the materials portion, depending on whether the contractor is acting as a reseller or as a consumer. The paperwork and the liability flow differently in each case.

Subcontractors add another layer. If a general contractor hires a subcontractor under a lump-sum arrangement, the sub is also treated as the consumer of its materials and should pay sales tax at purchase. But if the GC provides materials to the sub who then installs them, the GC needs to have paid sales tax on those materials already. The chain of custody matters. Failure to trace it creates gaps where tax ends up uncollected and unremitted, which is exactly what an auditor looks for.

Exemption and resale certificates are essential tools and are frequently misused or ignored. When a contractor builds for a tax-exempt entity, such as a government agency, a nonprofit hospital, or a religious organization, the contractor can often purchase materials for that specific job exempt from sales tax, but only by presenting the client’s exemption certificate to the supplier at the time of purchase and keeping a copy. Pulling an exemption retroactively after you have already paid tax is not straightforward. A resale certificate is used when a contractor genuinely acts as a reseller rather than a consumer of materials. Using the wrong form, or no form when one applies, is a common audit finding. The general rule: if you are the consumer, pay tax at purchase; if you are the retailer, charge tax to your client. Be consistent and document the basis for whichever position you take.

Capital improvement versus repair is a distinction that drives the treatment in many states. Materials that become a permanent part of real property under a qualifying capital improvement contract are often treated differently from materials used for repair and maintenance. Several states use a signed certificate from the property owner to certify that a project is a capital improvement rather than a repair. Without a properly executed certificate, the contractor may be required to collect sales tax on the entire contract price. This is one of the most audit-prone areas in all of construction accounting, and the rules are documented in your state revenue department’s construction guidance. The same capital-versus-repair line matters for federal purposes too: capitalized improvements are depreciated under IRS Publication 946 rather than expensed, while ordinary repairs are deductible currently under IRC §162, so the classification you reach for sales tax should be consistent with how you report the cost on your return.

Fabricated items create another wrinkle. If a contractor fabricates something off-site, such as a custom metal staircase, precast concrete panels, or millwork, and then installs it on the job site, the fabrication labor may be taxable even though installation labor would not be. This catches firms in the specialty trades. The IRC §460 long-term contract rules do not resolve this question. State law does, and it is worth confirming the treatment before you price the job.

Use tax is the flip side of sales tax and is equally important. If a contractor purchases materials from an out-of-state vendor who does not collect sales tax, the contractor owes use tax at the same rate. Use tax applies to the storage, use, or consumption of tangible personal property in the state. Contractors who buy heavily from out-of-state suppliers without tracking use tax obligations are accumulating liability on every purchase, and the dollar amounts on large material orders can be significant. Public works contracts add a final trap: the government entity is typically exempt as a consumer, but the contractor who actually purchases the materials is generally not, so do not assume the exemption transfers. Every exemption certificate, every purchase invoice showing tax paid, and every contract specifying lump-sum versus time-and-materials needs to be maintained and indexed by project. We help contractors review their sales and use tax compliance through our tax strategy consulting work. Start at the new client inquiry form.

Subcontractor payments are one of the highest-risk areas in construction accounting, both for IRS compliance and for state labor department scrutiny. We see this consistently: contractors who manage project execution well but whose back-office subcontractor tracking creates exposure that surfaces years later. The combination of 1099-NEC reporting, backup withholding rules, worker misclassification exposure, and licensing and insurance requirements makes this an area where errors are common and the consequences are out of proportion to what looks like a simple oversight.

The foundational rule: if you pay a subcontractor, an individual or an unincorporated business, $2,000 or more in a calendar year for services, you must file a Form 1099-NEC with the IRS and send a copy to the subcontractor by January 31 of the following year. The 1099-NEC replaced the 1099-MISC for nonemployee compensation starting with tax year 2020. Payments to corporations are generally exempt, with limited exceptions. The most important thing to collect before you write the first check, ideally before you execute any subcontract, is a completed Form W-9, which captures the subcontractor’s name, address, and Taxpayer Identification Number.

If a subcontractor refuses to provide a W-9 or provides one with an incorrect TIN, backup withholding kicks in at 24% under IRC §3406. You must withhold 24% of each payment and remit it to the IRS. In practice, legitimate subcontractors provide W-9s promptly because they understand you cannot process their payment otherwise. But in construction, where specialty trades are often hired on short turnaround, the pressure to pay first and collect paperwork later is real, and that approach creates compliance risk. Building a “no W-9, no payment” policy into your accounts payable workflow eliminates the problem at the source. Every construction accounting system we set up includes this as a non-negotiable step in vendor onboarding.

Worker classification is a separate and equally serious issue. Calling someone a subcontractor on a 1099 does not make them an independent contractor for tax or labor law purposes. The IRS applies a behavioral control, financial control, and type-of-relationship analysis to determine actual status, described in IRS worker classification guidance. Many states apply an even stricter standard, in some cases a three-part ABC test that presumes a worker is an employee unless the hiring entity can prove otherwise. If a worker uses your tools, works exclusively for you, follows your schedule, and has no independent business of their own, they are almost certainly an employee regardless of what your contract says.

Misclassifying employees as subcontractors is a major enforcement priority, and it has been for over a decade. The construction industry accounts for a disproportionate share of misclassification cases. Findings can include back payroll taxes, FICA, federal and state unemployment taxes, workers’ compensation violations, and potential liability for failure to pay prevailing wages to workers who should have been on payroll. A contractor with five years of misclassified workers faces liability that can threaten the business itself, and it tends to surface during workers’ comp audits, labor department investigations, and IRS examinations, often at the same time. The dollar exposure is substantial: the IRS can assess the employer share of FICA at 7.65% of wages plus penalties and interest going back three years, or six years in cases of fraudulent failure to file.

For legitimate independent subcontractors, businesses with their own crews, tools, insurance, and clients beyond you, the 1099 process is straightforward once W-9 collection is in order. The challenge is executing the year-end reconciliation accurately. Your accounts payable system needs to track vendor TINs and distinguish between corporations, which are 1099-exempt, and individuals or sole proprietors, which are 1099-required. A subcontractor who says “I’m incorporated” needs to show you an EIN that corresponds to a corporation, not an EIN issued to an LLC taxed as a disregarded entity, which is still reportable. Most construction accounting platforms can generate 1099-NEC data if configured correctly, but “configured correctly” means someone who understands the rules set it up that way.

The filing deadline is one of the earliest on the calendar. Both the copies sent to payees and the copies submitted to the IRS are due by January 31, while year-end reconciliation is often still in progress. Penalties under IRC §6721 start at $60 per return for timely corrections and increase to $310 per return for failures beyond August 1. Intentional disregard carries a minimum of $630 per form with no cap. For a construction company paying 50 subcontractors, missing the 1099 deadline is not a small problem. Many states also require state-level reporting of certain nonemployee compensation and have their own backup withholding regimes, so reconciling your federal filings with state records matters for surviving any state inquiry cleanly.

Subcontractor insurance documentation is where construction accounting and risk management overlap. Before a sub starts work, you should have a certificate of insurance on file showing general liability and workers’ comp, with your company listed as an additional insured. If a sub lets coverage lapse midproject, which happens regularly, and there is an incident, your exposure can be unlimited. Tracking certificate expiration across a base of 30 or 40 subs per year requires a system, whether built into the accounting software or managed separately. Many states also have lien laws that require a GC to hold contract funds in trust for the benefit of subcontractors and suppliers, so commingling those funds with operating accounts can expose principals to personal liability.

Finally, cost allocation for subcontractors needs to match the contract. If you pay a sub $180,000 for concrete work across three jobs, that $180,000 needs to be split accurately across three job cost ledgers, not coded to the largest job because it is easier. Inaccurate allocation distorts job profitability and, under the percentage-of-completion method governed by IRC §460, produces incorrect revenue recognition across those projects. Getting subcontractor accounting right requires the right systems and consistent execution throughout the year, not a year-end scramble. Our team handles construction accounting for GCs and specialty contractors, including 1099 preparation, W-9 workflow setup, and payroll classification review through our payroll compliance service. Reach us at the new client inquiry form.

Job costing mistakes in construction are expensive, not in the abstract sense of “this affects your numbers” but in the concrete sense of not knowing which contracts made money, overbilling or underbilling clients, failing to catch cost overruns before they become irreversible, and reporting the wrong taxable income. The mistakes we see repeatedly come down to a handful of structural problems that compound quietly over time.

The most common mistake is treating the business as one accounting unit rather than tracking costs at the job level. This happens most often with contractors who started small and grew without restructuring their bookkeeping. The owner knows roughly what came in and roughly what was spent, and the business looks profitable in aggregate, but they cannot tell you whether the $1.2 million renovation project made money or lost $80,000. That information gap makes it impossible to bid future projects at profitable margins, impossible to identify problem jobs before they spiral, and impossible to produce the job-level financial statements that bonding companies and lenders require for any meaningful credit line or surety capacity.

Misclassifying costs between jobs is a related problem. Direct costs, labor hours on a specific job, materials delivered to a specific site, subcontractor invoices for a specific project, should all be coded to the corresponding contract. Overhead costs, insurance premiums, equipment maintenance, office rent, supervision salaries, need to be allocated across jobs using a consistent methodology. When contractors code overhead to individual jobs inconsistently, or lump all labor into a single payroll account without job assignment, the job cost reports become meaningless and the percentage-of-completion calculations under IRC §460 become unreliable. The IRS can challenge PCM calculations that are not supported by credible underlying cost data, and the uniform capitalization rules of IRC §263A require certain indirect costs to be capitalized rather than expensed, which a sloppy overhead pool obscures.

Failing to capture all direct costs is the third common error. Labor is usually captured reasonably well because it flows through a defined payroll system. Materials are less reliable: purchases made on the fly with a company card, paid in cash at a supply house, or ordered verbally and invoiced weeks later often fall through the cracks. Equipment costs are frequently not tracked at all, even when rental or allocated depreciation under IRS Publication 946 represents a significant share of job costs. When direct costs are under-captured, your completion percentage under PCM overstates revenue, meaning you recognize income and pay tax on earnings that future costs will ultimately absorb.

Retainage is mishandled more often than not. The most common version of this mistake is treating retainage as revenue when it is billed rather than tracking it separately as a long-term receivable. Retainage should appear on your balance sheet as a distinct line item, tracked by contract, not lumped in with current accounts receivable. If your books do not separate regular contract billings from retainage, your cash flow projections will overstate near-term collections, your lender will not understand your liquidity position accurately, and your accountant will face difficulty determining the correct reporting treatment. On larger projects, retainage can represent hundreds of thousands of dollars, enough to materially affect every financial statement you produce.

Change order accounting is a consistent source of error that affects both financial reporting and tax compliance. Construction projects rarely execute exactly as contracted. Scope changes generate change orders with additional compensation, some approved and signed promptly, others disputed or pending verbal approval. IRS guidance on long-term contract modifications addresses how scope changes affect PCM, including when disputed change orders can be included in the contract price for completion percentage purposes. Contractors who handle change orders inconsistently, including revenue from favorable change orders immediately but deferring cost recognition from unfavorable ones, distort both their financial statements and their tax position.

Running the business on cash-basis records when the tax reporting requires accrual or percentage-of-completion is a structural error that masks the other problems. A contractor who looks at their bank account and says “we have $800,000 in, we have spent $600,000, so we made $200,000 this quarter” is not doing construction accounting. They might be over-recognizing revenue on jobs that are not complete, or under-recognizing on jobs where costs are ahead of billings. Under IRC §460, PCM is not optional for most long-term contracts. Preparing a return on the cash basis when PCM is required is incorrect, and IRS Publication 538 explains how accounting method changes are handled when a contractor’s current approach does not comply.

Overhead allocation methodology is underappreciated as a job costing variable. Many contractors allocate overhead as a flat percentage of direct labor, say 30% across all jobs. This is simple and defensible, but it may be wrong for the actual cost structure. An equipment-heavy contractor using a labor-based allocation understates job costs on equipment-intensive projects and overstates them on labor-intensive ones, making it impossible to compare profitability across project types. The methodology matters, and revisiting it periodically as the business changes is part of sound construction accounting practice. Not updating cost-to-complete estimates frequently enough produces the same distortion: a job showing 70% complete on stale estimates might actually be 55% complete, and the overstatement rolls through the P&L as tax on income that will not be earned.

The downstream consequences extend well beyond financial statements. Bonding capacity suffers because the CPA-prepared financials surety companies require look unreliable. Bidding suffers because historical cost data by project type is not trustworthy. Tax liability may be wrong in either direction: over-reported income means overpaid tax for potentially multiple years, while under-reported income means IRS exposure and potential state underpayment penalties. Fixing these problems requires the right accounting software configured for job costing, staff who understand construction rather than just general ledger bookkeeping, and a CPA who reviews job cost reports alongside the tax return and flags discrepancies before they become IRS issues. Our team works with construction companies to build or repair their accounting systems and make their tax filings match their actual operations. Contact us through the new client inquiry form, or review our bookkeeping service for what we provide to construction clients.