By Daniel Jahn, CPA — Contractor’s Ledger
If you’re a specialty trade contractor doing commercial work, there’s a good chance your bonding company, your bank, or a GC you’re trying to prequalify with has asked whether your financials are prepared using the percentage-of-completion method.
This guide explains what percentage-of-completion (POC) accounting is, how it compares to the cash-basis or completed-contract approaches most small contractors use, and why it matters for your bonding, banking, and financial decision-making.
The Core Problem With Cash-Basis Accounting for Contractors
Most small specialty trade contractors start out on cash-basis accounting. Revenue is recognized when you invoice. Costs are recognized when you pay. It’s simple, it’s intuitive, and it works reasonably well for small residential service work.
But when you start doing long-duration commercial projects, cash-basis accounting creates a distorted picture of reality.
The distortion: Imagine a $600,000 commercial plumbing project that takes six months to complete. Under cash-basis accounting:
- Month 1: You invoice for mobilization — $30,000. You record $30,000 of revenue.
- Months 1–5: You incur $480,000 in costs (labor, materials, subs). Each month, your P&L shows a loss.
- Month 6: Final invoice — $570,000 goes out. Your books show a $570,000 revenue month.
The result is monthly financial statements that swing wildly from loss months to a huge profit month — none of which reflect actual business performance. You can’t make meaningful decisions from those numbers. Your bank can’t assess your credit. Your surety can’t evaluate your financial position.
What Percentage-of-Completion Accounting Does Instead
Percentage-of-completion accounting ties revenue and cost recognition to the percentage of work actually completed on each contract, measured period by period.
How it works:
- At the end of each accounting period (month, quarter), you calculate how far along each open project is
- Revenue recognized = percentage complete × total contract value
- The difference between recognized revenue and billed-to-date is your underbilling (or overbilling)
Using the same $600,000 plumbing project:
| Month | Costs Incurred | % Complete | Revenue Recognized | Monthly Profit |
|---|---|---|---|---|
| 1 | $60,000 | 12.5% | $75,000 | $15,000 |
| 2 | $90,000 | 31.3% | $112,500 | $22,500 |
| 3 | $110,000 | 54.2% | $137,500 | $27,500 |
| 4 | $100,000 | 75.0% | $125,000 | $25,000 |
| 5 | $80,000 | 91.7% | $100,000 | $20,000 |
| 6 | $40,000 | 100.0% | $50,000 | $10,000 |
| Total | $480,000 | — | $600,000 | $120,000 |
Now every month shows a profit that reflects the actual margin on the project, proportional to work performed. Your monthly financial statements are meaningful. Your year-to-date profitability makes sense.
How Percentage of Completion Is Measured
There are two primary methods for measuring percentage of completion:
1. Cost-to-Cost Method (Most Common)
Percentage complete = Costs incurred to date ÷ Total estimated cost at completion
This is the most widely used method for specialty trade contractors. It requires maintaining accurate cost estimates throughout the project — as costs change, your estimate to complete must be updated.
2. Units-of-Work Method
Percentage complete based on physical progress — linear feet of pipe installed, tons of steel erected, percentage of drawings approved. This can be more accurate for certain types of work but requires physical progress reporting.
Most specialty trade contractors use the cost-to-cost method because it integrates directly with their existing job cost accounting.
What Percentage-of-Completion Accounting Requires
POC accounting is more demanding than cash-basis. It requires:
Current cost estimates. You need an estimate of total cost at completion for every open project. As conditions change (labor cost overruns, scope additions, material price changes), the estimate must be updated. This means your project managers and accounting function need to communicate regularly.
A WIP schedule. The WIP schedule is the output of POC accounting — it shows the completed percentage, earned revenue, billed-to-date, and overbilled/underbilled position for every open contract. Read our WIP schedule guide for a full explanation.
CPA oversight. POC accounting is significantly more complex than cash-basis. It should be implemented and maintained by an accountant with construction accounting experience. Done incorrectly, it can be worse than cash-basis.
Why Bonding Companies Require Percentage-of-Completion
Surety underwriters for specialty trade contractors in the commercial sector almost universally expect to see financial statements prepared using the percentage-of-completion method. Here’s why:
Cash-basis financials hide the truth about contract risk. A cash-basis balance sheet doesn’t show your overbilling (a liability to perform future work) or your underbilling (money owed but not yet invoiced). These are critical components of your true financial position.
POC statements show forward-looking indicators. The WIP schedule shows surety underwriters whether your open contracts are profitable based on current cost estimates. This forward-looking data is impossible to extract from cash-basis statements.
Industry standard. Construction accounting under GAAP uses the percentage-of-completion method for long-duration contracts. Sureties are evaluating your business against that standard.
When to Switch to Percentage-of-Completion
If all of these are true, you probably don’t need POC accounting:
- Your projects are all short-duration (under 3 months)
- Your revenue is primarily service and repair work with no multi-month contracts
- You don’t need bonding or have a very small, stable bond line
If any of these are true, POC accounting is worth discussing:
- You have commercial contracts lasting more than 3 months
- You’re pursuing bonding or trying to increase your bond line
- Your banker wants to see financial statements that show your contract position
- You’re doing GC prequalification and they want percentage-of-completion financials
- Your monthly P&L swings wildly depending on billing timing
How Contractor’s Ledger Implements Percentage-of-Completion
We implement and maintain percentage-of-completion accounting for specialty trade contractors. That includes:
- Setting up the accounting software to handle POC revenue recognition
- Working with you to establish and maintain project cost estimates
- Preparing monthly WIP schedules that show your over/underbilled position
- Producing monthly financial statements on a percentage-of-completion basis
- Coordinating with your bonding agent to ensure the format meets their requirements
The transition from cash-basis to POC accounting doesn’t happen overnight, but it’s manageable. Most of our clients complete the transition within 60–90 days.
If you’re doing commercial work and haven’t moved to percentage-of-completion accounting yet, the question isn’t whether to — it’s when.
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Daniel Jahn is a licensed CPA and founder of Contractor’s Ledger, a construction accounting firm serving specialty trade contractors nationwide.
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