Cash Basis vs Accrual Basis: IRS Rules and How to Switch

Cash basis vs. accrual basis accounting comes down to timing: the cash method records income when payment arrives and expenses when you pay them, while the accrual method records income when you earn it and expenses when you incur the obligation, regardless of when money moves. That single difference shapes your reported profit, your tax bill, and whether lenders take your financial statements seriously. For some businesses, the IRS makes the choice for you.

The Core Difference, in One Example

Say your business performs $10,000 in services and pays $3,000 in wages during December, but only collects $2,000 from invoices sent in prior months. Under the cash method, December shows $2,000 in revenue and $3,000 in expenses, a $1,000 loss. Under the accrual method, December shows $10,000 in revenue and $3,000 in expenses, or $7,000 in income. Same month, same business, two very different pictures.

Which picture is “right” depends on what you want to know. The cash number tells you what hit your bank account. The accrual number tells you what the business actually accomplished. Both are legitimate; they answer different questions.

How the Cash Method Works

Under the cash method, revenue lands on your books when the money lands in your account, and expenses count when the check clears or the card is charged. Finish a $5,000 project in December but get paid in January? That’s January income. Get a utility bill in December but pay it on January 10? January expense.

Simplicity is the main appeal. Your books mirror your bank account, so you always know how much actual money you have. Small businesses, sole proprietors, and service firms without inventory tend to pick this method because it keeps bookkeeping manageable and leaves some room for year-end tax planning.

The weakness is distortion. A month where you finally collect on old invoices looks wildly profitable. A month where clients drag their feet looks like a disaster. Neither snapshot reflects the work you actually did.

You Can’t Just Ignore Money That’s Available

The cash method does not let you dodge income by refusing to pick up a check. Under the constructive receipt doctrine, income counts as received when it is credited to your account or otherwise made available to you without restriction, even if you never physically touch it.¹ A check that arrives December 29 is December income whether you deposit it that day or leave it in a drawer. Bank interest credited to your account in December is December income even if you don’t withdraw it.

The exception is a genuine restriction on your control. A bonus credited to your account but locked until the next quarter isn’t constructively received until you can actually draw on it.² Artificially delaying access to money you could have collected is the kind of thing that gets flagged on audit.

How the Accrual Method Works

Under the accrual method, revenue is recorded when you complete the work or deliver the product and have the right to collect. Expenses are recorded when you become obligated to pay, not when the payment goes out. Finish that $5,000 project in December? December revenue, even if cash arrives in January. The wages you owe for the work also hit December.

Two principles drive this. Revenue recognition says you record income when you’ve earned it and collection is reasonably assured. The matching principle says you record expenses in the same period as the revenue they helped produce. Together they give a more accurate view of what the business did during a given period.

The tradeoff is complexity. You have to track accounts receivable (money owed to you), accounts payable (money you owe), and deferred revenue (money collected for work you haven’t done yet). Your books will often show profits you can’t spend because the cash hasn’t arrived, or expenses you haven’t paid. Cash flow management takes more work when your profit-and-loss statement and your bank balance tell different stories.

One Advantage: Bad Debt Deductions

Accrual-basis businesses can deduct receivables that turn out to be uncollectible. Because you reported the income when you earned it, you get a deduction when the customer stiffs you. A debt that becomes completely worthless is deductible in the year it goes bad, and partially worthless debts may qualify for a partial deduction.³

Cash-basis businesses rarely get this deduction. If a client never pays, there’s nothing to write off because the income was never reported in the first place.

What Each Method Does to Your Financial Statements

The difference shows up most sharply during rapid growth or seasonal swings. An accrual-basis business booking a lot of new work shows higher income immediately, even if the cash hasn’t arrived. A cash-basis business in the same spot might look flat because the money lags the work.

The balance sheet looks different too. Accrual-basis balance sheets carry accounts receivable and accounts payable, showing the full picture of money owed in both directions. Cash-basis balance sheets are leaner, usually just cash, fixed assets, and debt. Lenders and investors almost always prefer accrual statements because they reveal obligations the cash method hides.

Who the IRS Forces to Use Accrual

You don’t always get to pick. The Internal Revenue Code restricts the cash method for three types of taxpayers: C corporations, partnerships that include a C corporation as a partner, and tax shelters.⁴ These entities must use the accrual method unless they qualify for an exception.

The Gross Receipts Test

The main exception is the small business taxpayer rule. If your average annual gross receipts over the three preceding tax years fall below the inflation-adjusted threshold, you can use the cash method even as a C corporation or a partnership with a corporate partner. The statutory base amount is $25 million, adjusted each year for inflation. For tax years beginning in 2025, the threshold is $31 million.⁵ Check the current year’s figure before relying on this test.⁴

Two other exceptions apply regardless of gross receipts. Farming businesses and qualified personal service corporations (engineering, architecture, accounting, consulting, and similar fields where the principal asset is employee expertise) can use the cash method even as C corporations.⁴ Tax shelters get no exception at all.

Inventory Businesses

Businesses that produce or sell goods traditionally had to use accrual for purchases and sales and maintain formal inventories. Since the Tax Cuts and Jobs Act, small business taxpayers meeting the gross receipts test can skip traditional inventory accounting entirely.⁶ These businesses can either treat inventory as non-incidental materials and supplies (deducting the cost when goods are sold rather than when purchased) or follow whatever inventory method they use on their financial statements. Before 2018, a small retailer or manufacturer that wanted to use cash often had to maintain a parallel accrual system just for inventory. That dual-tracking burden is gone for qualifying small businesses.

GAAP Is a Separate Question

Tax rules and financial reporting rules are different systems. All publicly traded companies must use accrual accounting for the financial statements they file with the SEC, and most large private companies follow the same standard for lenders and investors. A business that qualifies for cash-basis tax reporting but uses accrual for its financial statements will maintain two sets of books. That is common and perfectly legal.

You Don’t Have to Pick Just One

The tax code allows a hybrid method, a combination of cash and accrual, as long as the combination clearly reflects your income and you apply it consistently.⁷ A common version uses cash for everyday income and expenses while tracking long-term assets, inventory, and certain liabilities on an accrual basis.

If you run more than one trade or business, you can use a different accounting method for each. A dentist who also owns a rental property could use cash for the practice and accrual for the rental, as long as each method clearly reflects the income of that specific business.⁷ Hybrid methods aren’t allowed under GAAP for external financial reporting, so this is primarily a tax tool.

If You Want to Switch

Changing your accounting method requires IRS approval. You request it on Form 3115, Application for Change in Accounting Method, whether you’re going cash to accrual, accrual to cash, or changing how you treat a specific category of income or expense.⁸ Even changes that qualify for automatic consent still require the form.

Switching methods also triggers a Section 481(a) adjustment, a one-time correction that prevents income or expenses from falling through the cracks or being counted twice. It calculates the cumulative difference between what you reported under the old method and what you would have reported under the new one, then adds or subtracts that amount from your taxable income.⁹ If the adjustment works in your favor, you take the full deduction in the year of the change. If it works against you, you spread the additional income evenly over four years, softening the impact.¹⁰

File Form 3115 before you change anything. The automatic consent process exists to make voluntary changes painless, and the IRS has authority to force a method change (and compute the adjustment on its terms) if it finds you switched without permission or used a method that doesn’t clearly reflect income.⁷

1
Internal Revenue Service. Publication 538, Accounting Periods and Methods
2
GovInfo. 26 CFR 1.451-2 – Constructive Receipt of Income
3
Office of the Law Revision Counsel. 26 USC 166 – Bad Debts
4
Office of the Law Revision Counsel. 26 USC 448 – Limitation on Use of Cash Method of Accounting
5
Internal Revenue Service. Questions and Answers About the Limitation on the Deduction for Business Interest Expense
6
Office of the Law Revision Counsel. 26 USC 471 – General Rule for Inventories
7
Office of the Law Revision Counsel. 26 USC 446 – General Rule for Methods of Accounting
8
Internal Revenue Service. About Form 3115, Application for Change in Accounting Method
9
Office of the Law Revision Counsel. 26 USC 481 – Adjustments Required by Changes in Method of Accounting
10
Internal Revenue Service. Rev. Proc. 2015-13