Form 3115 Explained: Switching Accounting Methods
When a business needs IRS consent to change how it reports an item, automatic versus advance-consent changes, and the catch-up adjustment.
Reviewed by the Fairlight Accounting cross-border tax team — U.S. & Canadian Tax Desks
Form 3115 is the application a business files to change an accounting method — its overall method, such as cash or accrual, or the treatment of a specific item, such as depreciation or inventory. Many changes are automatic: consent is granted by filing the form. A one-time Section 481(a) adjustment prevents skipping or double-counting.
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What counts as a change in accounting method?
A change in method affects when an item is reported, not whether it is reported. Using the same treatment on two consecutive returns usually establishes a method. Examples:
- Switching from cash to accrual, or accrual to cash
- Changing how inventory is valued or whether it is kept at all
- Correcting depreciation that used the wrong recovery period or method, including depreciation never claimed
- Adopting the tangible property rules for repairs versus improvements
- Changing the timing of advance payments
Fixing a math error or a one-time posting mistake is not a method change; that is corrected by amended return.
Automatic or advance consent?
| Feature | Automatic change | Advance (non-automatic) consent |
|---|---|---|
| Listed in IRS list of automatic changes | Yes | No |
| User fee | None | Yes |
| When to file | Original with the timely filed (including extensions) return for the year of change; duplicate copy to the IRS | During the year of change |
| IRS response | None needed | Ruling letter |
| Audit protection for earlier years | Generally yes | Generally yes |
The current list of automatic changes is Revenue Procedure 2025-23, and each automatic change has a designated change number that goes on the form.
How does the Section 481(a) adjustment work?
The adjustment captures the cumulative difference between the old and new method as of the start of the year of change. If it increases income, it is generally spread over four years — the year of change and the next three — though a business can elect to take a positive adjustment under $50,000 all at once. If it reduces income, it is taken entirely in the year of change.
Example. A business never claimed depreciation on equipment for three years. Instead of amending three returns, it files Form 3115 and deducts all the missed depreciation in the current year as a negative adjustment.
Why does audit protection matter?
Filing a qualifying Form 3115 generally prevents the IRS from requiring the same change for earlier years under examination. Waiting until the IRS raises the issue usually removes that protection and the favorable spread.
Frequently asked questions
Can I change methods by simply filing differently this year?
No. Without consent, the change is improper and the IRS can reverse it.
Is Form 3115 needed when a small business first adopts a method?
No. A business adopts its methods on its first return. Form 3115 is for changes after that.
Can several changes go on one form?
Some related automatic changes can be combined on a single Form 3115; others require separate forms.
Does the form go to the IRS address for my return?
The original is attached to the return; the duplicate for automatic changes goes to the IRS office named in the instructions.
Official sources
The IRS explains: “File this form to request a change in either: an overall method of accounting or the accounting treatment of any item.” — Internal Revenue Service, About Form 3115, Application for Change in Accounting Method, https://www.irs.gov/forms-pubs/about-form-3115
The IRS explains: “Once you have set up your accounting method and filed your first return, generally, you must receive approval from the IRS before you change the method.” — Internal Revenue Service, Publication 538 (01/2022), Accounting Periods and Methods, https://www.irs.gov/publications/p538
Next step
Fairlight Accounting handles U.S. domestic, cross-border (U.S.–Canada), and international tax returns, plus bookkeeping, payroll, and CFO advisory. Our U.S. Tax Desk prepares Form 3115 for method changes and missed-depreciation catch-ups. See pricing or book a free fit call.
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