You Paid Tax on Money You Never Collected
Last year was a great year. Then the return came back, and you owed tax on invoices your customers still hadn’t paid.
“How do I owe tax on money I don’t have?”
Fair question. And the answer usually isn’t a bad CPA or a bad year. It’s one box on your return.
That box is your accounting method.
The cash vs. accrual accounting decision for contractors gets treated like a bookkeeping detail. It isn’t. It decides when you pay tax, and that makes it a cash flow decision the owner should make on purpose. The real question isn’t “Which method is correct?” It’s “Is my tax clock running ahead of my cash?”
Bookkeeping Method vs. Tax Timing Decision
Here’s the difference in plain terms.
- Accrual starts the tax clock when you earn the income, generally when the work is done and you have the right to bill. You frame the job in November. You invoice in December. You get paid in March. For tax purposes, that income generally already landed in the year you earned it.
- Cash starts the clock when the money actually hits your account, and you deduct expenses when you actually pay them.
Cash is simple. Boring. It matches how most owners already think about their business: money in, money out. That’s why most builders belong on cash, and why the method choice deserves an owner’s attention instead of a default.
Cash vs. Accrual Accounting for Contractors: The Essentials
A few table-stakes facts, generally speaking, before we get to the framework:
- Who can use cash. Businesses that pass the federal gross receipts test can generally use the cash method. The test looks at your average annual gross receipts over the prior three tax years. For tax years beginning in 2026, the inflation-adjusted threshold is $32 million ($31 million for 2025), and it moves each year. That covers most owner-run trade firms.
- Entity matters. The gross receipts test matters most for C corporations and partnerships with a C corporation partner. Separately, a business the tax code treats as a “tax shelter” generally can’t use cash, regardless of size. That can include an S corporation, partnership, or LLC in a loss year if more than 35% of the loss goes to owners who don’t actively manage the business.
- Long-term contracts. Smaller contractors whose jobs are expected to finish within two years are generally exempt from the percentage-of-completion requirement for those contracts, which is what opens the door to cash or completed-contract methods.
- How you switch. A change from accrual to cash is generally an automatic change. Your CPA files Form 3115 with your timely filed return for the year of change, plus a copy to the IRS. No amended returns.
- The catch-up adjustment. The switch includes a one-time Section 481(a) adjustment so nothing gets taxed twice or deducted twice. For a typical contractor with more receivables than payables, that adjustment is negative, and a negative adjustment is generally taken in full in the year of change.
- The five-year rule. Once you use the automatic procedure, you generally can’t use it again to change the same method within five years. Going back sooner usually means requesting IRS consent, with a user fee. Plan as if you’re committing.
- California generally conforms to the federal small business accounting method rules for tax years beginning on or after January 1, 2019. Individual facts, and current California treatment, still need review.
The Three-Clock Test
Before any owner switches, I use a framework I call the Three-Clock Test. Every construction business runs on three clocks. The goal isn’t to make them match. It’s to know what each one is doing and decide on purpose.
1. The Tax Clock: When does the IRS count your income?
Pull last year’s return. Check the method box. Then compare year-end receivables to year-end payables. If receivables are much larger, you likely paid tax on money that was still sitting in your customers’ accounts. That gap is roughly what cash basis would have shifted into the next year.
2. The Cash Clock: When does money actually move?
Look at a normal month. How long after you invoice does the money actually arrive? When do subs, suppliers, and payroll go out? If collections lag your billing by weeks or months, accrual keeps taxing you on money you’re still waiting for. Cash basis generally fits that pattern.
3. The December Clock: What lands in the last two weeks of the year?
Cash basis has its own trap. A pile of checks clearing on the 28th with nothing going out until January is a tax bill you built yourself. Before year end, look at what’s scheduled to come in and what’s due to go out. The goal isn’t to game the calendar. It’s to see the bill coming while you can still plan for it, with your CPA, before December is over.
When all three clocks are understood, the method choice gets easy. When one is ignored, it gets expensive.
Four Assumptions That Create Expensive Surprises
“My bookkeeper picked the method, so it must be right.”
Often the method was set when the business was tiny and never revisited. Nobody owns the decision. That’s the problem.
“Cash basis means I can just hold checks until January.”
No. Money you’ve received, or that’s available to you without restriction, generally counts when you get it. Cash basis is a timing tool, not a place to hide deposits.
“Cash basis always means a smaller tax bill.”
No. Cash basis changes when you pay, not whether you pay. A heavy December on cash can produce a bigger bill than accrual would have. That’s why the December Clock matters.
“I can switch back if next year looks different.”
Not easily. The five-year rule means this is a multi-year commitment. Look at where the business is heading, not just last year.
A Fictional Example: Carlos and the $80,000 Gap
Consider a fictional California commercial general contractor in Hayward doing $4.8 million in annual revenue. Call the owner Carlos. His return is on accrual.
At year end, Carlos has $265,000 in unpaid customer invoices, including retention not yet due. He owes $185,000 to subs and suppliers. Under accrual, that $80,000 net gap is taxed this year, even though none of it is in his bank account.
- Tax Clock: Depending on his combined federal and California rates, that gap could mean a five-figure tax bill funded from his operating account while he’s waiting on draws.
- Cash Clock: Most of his collections arrive 45 to 75 days after invoicing, while payroll and subs go out on time. His collections lag. Cash basis would generally fit his pattern.
- December Clock: Last December, $120,000 in progress payments cleared between the 22nd and the 30th, while $95,000 in sub and supplier bills weren’t due until January. On cash, that pattern would have pulled a large chunk of income into the year with few offsetting payments. So the plan includes a year-end review with his CPA in early December, every year, before the checks land.
If his CPA files the automatic change, the year-of-change adjustment would generally be a negative $80,000, reflecting income he’d already been taxed on. That prevents double taxation when those invoices are collected.
The framework didn’t guarantee a savings figure. It revealed that his tax clock was running months ahead of his cash, and it made the switch a decision instead of a surprise.
The Bigger Reframe
The accounting method isn’t your bookkeeper’s business. It’s yours.
It decides when you pay tax, which decides how much cash you have to run jobs, make payroll, and bid the next project. Clean books are not the goal. Books that support the decision are.
Bottom Line
Accrual taxes you when you earn it. Cash taxes you when you collect it. Most owner-run trade businesses are eligible for cash. Not all of them belong there. Run the Three-Clock Test before you switch. Paying tax on money you haven’t collected isn’t a tax problem. It’s a cash flow problem with a tax bill stapled to it.
Frequently Asked Questions
Can a construction company use the cash method of accounting? Generally yes, if it passes the gross receipts test (a three-year average of $32 million for tax years beginning in 2026, or $31 million for 2025) and isn’t a tax shelter. Long-term contract rules and entity type still need review.
How do I switch from accrual to cash basis? Your CPA generally files Form 3115 as an automatic change with the timely filed return for the year of change. No amended returns are required.
Will I pay tax twice when I switch? No. The Section 481(a) adjustment is designed to prevent income from being taxed twice or expenses from being deducted twice.
Can I switch back to accrual later? Generally not through the automatic procedure within five years. An earlier change usually requires IRS consent and a fee.
Does cash basis mean I pay less tax? Not necessarily. It generally changes when income is taxed, not whether it is. A December full of late-arriving checks can still create a large bill.
Book an Introductory Call
I help construction owners connect their tax method and their cash timing into one plan, so the tax bill is a decision instead of a surprise.
If your firm is doing roughly $2 million to $20 million in revenue and you paid tax on invoices that were still unpaid at year end, book an introductory call with me.
This article is general financial and tax information, not advice for your specific situation. Accounting method changes depend on your entity, contracts, and history, and should be reviewed with your CPA before filing.
