Form 3115: How to Change Your Business Accounting Method and Claim Catch-Up Deductions

Form 3115 (Application for Change in Accounting Method) is the mechanism for changing from one accounting method to another under IRC 446. The IRS requires consistency in accounting methods from year to year, so switching methods requires either automatic consent (filing Form 3115 with the return) or advance consent (filing with the IRS and waiting for approval). The most powerful feature of a method change is the Section 481(a) adjustment, which computes the cumulative difference between the old method and the new method as if the new method had always been used. A positive 481(a) adjustment (additional income) is spread over 4 years. A negative 481(a) adjustment (additional deductions) is taken entirely in the year of change. This makes Form 3115 a significant tax planning tool: a cost segregation look-back, for example, can generate hundreds of thousands of dollars in catch-up depreciation deductions in a single year.

How does a Form 3115 method change work in practice?

What triggers a required change in accounting method?

The IRS requires a change in accounting method when your current method doesn’t clearly reflect income (IRC 446), when your gross receipts exceed the threshold for using the cash method under IRC 448 ($32 million average for the prior 3 years, for tax years beginning in 2026), or when a new tax law mandates a different method. Voluntary changes (such as switching from cash to accrual to better match revenue and expenses) require filing Form 3115 with your tax return. Most accounting method changes require a Section 481(a) adjustment, which captures the cumulative difference between the old and new methods. A positive 481(a) adjustment (additional income) is spread over 4 years, while a negative adjustment (additional deduction) is taken entirely in the year of change. Changes made under the automatic consent procedures (Rev. Proc. 2015-13 for the procedures and Rev. Proc. 2025-23 for the list of automatic changes, or their successors) don’t need advance IRS approval but must follow detailed filing requirements.

Should I use cash basis or accrual basis accounting for my small business?

Cash basis records income when received and expenses when paid, making it simpler and giving you more control over timing. Accrual basis records income when earned and expenses when incurred, regardless of payment timing, providing a more accurate picture of profitability. The IRS requires accrual for businesses with inventory that have average annual gross receipts exceeding $32 million (for tax years beginning in 2026; $31 million for 2025). Below that threshold, you can choose either method. Most small service businesses use cash basis because of its simplicity and the ability to time income and deductions for tax planning. Once you choose a method, switching requires filing Form 3115 and may trigger a Section 481(a) adjustment that spreads the transition impact over four years.

Related guides:

• Form 3115 Accounting Method Changes: When to Switch and How Section 481(a) Adjustments Work

• Form 3115 Accounting Method Changes: When to Switch and How Section 481(a) Ad…

• Cash vs. Accrual Accounting: Tax Implications for Small Businesses

• Cash vs. Accrual Accounting for Small Businesses: Which Method to Use

How often should a small business reconcile its accounts?

Monthly reconciliation is the minimum standard for any business, but weekly reconciliation catches errors faster and makes month-end closing significantly easier. Bank reconciliation compares your accounting records to bank statements to identify timing differences (outstanding checks, deposits in transit) and errors (duplicate entries, missed transactions). Credit card reconciliation should happen monthly at minimum, matching each statement charge to a recorded transaction with the correct expense category and ensuring no unauthorized charges slipped through. Businesses with high transaction volume (retail, restaurants, e-commerce) benefit from daily point-of-sale reconciliation, which catches discrepancies before they compound into material misstatements at year-end.

This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.