How to fill out Form 3115 for missed depreciation

If your business just discovered that a piece of property has been sitting on the books without the depreciation it was entitled to, correcting it does not mean amending every return since the asset was placed in service. It means filing Form 3115, and the form asks you to complete only a portion of its parts and lines for this specific kind of change.

For a missed depreciation correction, you check the box for a change in depreciation or amortization, enter designated change number 7 on line 1a, and complete Part I, Part II, and Part IV, along with the Schedule E statement that identifies the property involved. The total amount you failed to claim in prior years becomes one negative Section 481(a) adjustment, reported on Part IV and deducted in full on the return for the year of change. Part III, which governs non-automatic requests that go to the IRS National Office with a user fee attached, does not apply to this kind of filing at all, and knowing that up front saves a lot of wasted reading.

DCN 7 covers a missed or wrong depreciation method, not every depreciation question

Designated automatic accounting method change number 7 is the entry on line 1a for a change from an impermissible method of accounting for depreciation to a permissible one. The IRS treats a company as having adopted a method the moment it appears on two consecutively filed returns, even when that method is wrong or the company never noticed it had one. Claiming no depreciation at all on an asset for several years counts as an impermissible method under this rule, the same as claiming the wrong recovery period or the wrong convention would.

Three eligibility conditions matter more than the rest for this specific change. The property has to still be held by the company as of the beginning of the year of change, since a different set of rules governs assets that have already been sold or retired. The requested year cannot be the company's final year in that trade or business, with narrow exceptions the instructions carve out. And the company cannot have made or requested a change for the same item during any of the five tax years ending with the year of change, which is worth checking against old filings before you assume the automatic route is open.

DCN 7 also has a boundary worth stating plainly, because it comes up constantly and it is the single most common way a Form 3115 depreciation filing goes wrong. You do not file Form 3115 to make or revoke an election under Section 167, 168, 179, or 197. You do not file it to change a placed-in-service date. You do not file it to change a useful life, except where the Code assigns a specific one.

A missed bonus depreciation or Section 179 election is a different problem with a different fix. Specific procedures exist for addressing late elections, including Rev. Proc. 2020-25 and subsequent IRS guidance that allow certain elections to be made via amended returns in qualifying circumstances, but the rules are fact-specific and have changed over time. If your situation involves a missed election rather than a straightforwardly wrong depreciation method, confirm the correct approach with a tax advisor before assuming Form 3115 is the right vehicle.

Start at the top of the form, the type of change and the DCN

Page 1 of Form 3115 asks you to check a box for the type of accounting method change being requested before you get into any of the numbered parts. For a depreciation catch-up, check "depreciation or amortization," which covers a change in the depreciation method or recovery period, the treatment of dispositions, and a few related items.

Line 1a is where the DCN itself goes. Enter 7. Line 1b only comes into play if the change is not on the published list, which will not be the case here, so it stays blank. Line 2 asks whether any of the eligibility rules restrict the applicant from filing the requested change using the automatic change procedures. For an ordinary eligible depreciation-method correction, the answer is No. If a rule would otherwise restrict the request but published guidance waives it, follow the line-specific instruction for that waiver and attach the required explanation. Do not check Yes simply because the applicant qualifies for the automatic procedure. The question is about restrictions, not about eligibility.

Which parts of the form you actually complete

The instructions include a table matching each type of request to the parts that must be completed, and it settles a question that trips people up before they have written a single number. An automatic change, which is what DCN 7 is, requires Part I, Part II, and Part IV. Part III exists only for non-automatic requests, the ones that go to the IRS National Office in Washington with a user fee and no deemed consent while you wait for an actual ruling. If your filing qualifies for DCN 7's automatic procedure, and for a plain missed-depreciation correction it usually does, Part III gets skipped entirely.

That distinction is worth sitting with for a moment, because it changes the entire cost and timeline of the filing. The automatic route has no fee, no waiting period, and the original copy simply rides along with your regular tax return. The non-automatic route can run into the thousands of dollars in fees and months of back-and-forth with the IRS before you get an answer. Confirming DCN 7 eligibility at the start of the process is not a formality. It is the decision that determines whether this is a quick attachment to your return or a separate, lengthy filing project.

Part II covers your filing history and your exam status, not your numbers

Part II applies to every Form 3115, automatic or not, and most of its lines are about the company's situation rather than the depreciation calculation itself.

Lines 6 through 10 ask whether the company is under IRS examination, before an appeals office, or in front of a federal court, and if so, what audit protection category applies. Audit protection is the benefit that keeps the IRS from reopening the prior years covered by the change once the method change is granted. For a company that is not currently under exam, the answer is simply "not under exam," which is the easiest box on the whole form.

Lines 11 through 12 ask about prior method changes for the same item within the last five years, echoing the eligibility check from earlier. Line 13 asks whether this is also an overall method of accounting change, such as cash to accrual, and the answer for a depreciation-only correction is no, which means Schedule A gets skipped along with it. Lines 19a and 19b concern the gross receipts test that some other DCNs require, and it generally does not gate DCN 7 eligibility the way it gates a cash-method change, though qualifying small taxpayer status can still unlock a shorter version of the form, covered next.

One detail specific to DCN 7 is worth flagging because it is easy to miss. Lines 16a and 16b, which normally ask non-automatic filers for a full legal explanation of their proposed method, also apply to a short list of automatic changes that includes DCN 7. In practice, this means attaching a statement that provides the pertinent facts and legal authority explaining why this specific property's proposed depreciation method is permissible. A bare citation to the procedural Rev. Proc. 2015-13 is not sufficient on its own. The statement needs to identify the property, explain why the prior method was impermissible, and explain why the proposed method is the correct one under the applicable Code section, regulation, or IRS guidance. It does not need to be lengthy, but it must address the substance of the proposed change, not just the filing procedure.

Qualifying small taxpayers get a real shortcut here. DCN 7 is one of the changes eligible for a reduced filing requirement under the current revenue procedure, which lets an eligible small taxpayer complete only certain lines and schedules instead of the full form. Rev. Proc. 2025-23, Section 6.01, defines a qualified small taxpayer for the DCN 7 reduced-filing requirement as one with average annual gross receipts of $10 million or less for the three preceding tax years, determined under the cited regulation. This is not the $25 million threshold that applies to some other provisions. The reduced filing omits certain lines but does not waive line 26 or the supporting asset calculation, so the Section 481(a) amount and its attached statement are still required. Confirm current eligibility with your preparer at the time of filing, since the governing revenue procedure can be updated.

Schedule E names each asset, it does not summarize them

Every applicant requesting a depreciation or amortization change completes Schedule E, and Schedule E is short on the printed form itself because almost all of the substance lives in an attached statement rather than on the page.

For each piece of property involved in the change, the statement needs to describe the property, state its type, give the year it was placed in service, and describe its use in the company's trade or business or income-producing activity. It also needs to state the type and amount of any tax credit, subsidy, or grant claimed with respect to the property, along with any basis adjustment the Code requires as a result.

For a company correcting several years of missed depreciation on one asset, this is a single, fairly short paragraph. For a company correcting the treatment of a dozen pieces of equipment purchased across several years, it is a genuine schedule, with each item's placed-in-service date and calculation traced back to its own starting point. The level of detail the instructions ask for is exactly the level that makes the Section 481(a) computation verifiable rather than asserted.

Part IV turns the shortfall into one number

Part IV is where the dollar amount lives, and it is short relative to how much weight it carries.

Line 25 is not a question about whether a Section 481(a) adjustment exists. It asks whether published guidance requires or permits the requested change on a cut-off basis, meaning a prospective-only approach with no adjustment for the prior-year difference. For an ordinary DCN 7 catch-up that uses a cumulative Section 481(a) adjustment, the answer is No. If the answer were Yes, the instructions direct the filer not to complete lines 26 through 29 at all, which is why getting this right matters.

Line 26 is where the net Section 481(a) adjustment itself is entered, reported as an income decrease with a negative sign for a catch-up situation. The instructions require an attached statement showing how the amount was computed along with an explanation of the methodology, detailed enough that the IRS could verify the number rather than simply accept it on faith. This is the same statement Schedule E's asset-level detail feeds into.

When the amount is negative, meaning the company is owed a deduction because it underclaimed depreciation, the full adjustment comes off taxable income in the single year of change. When the amount is positive, meaning the company had actually been claiming too much and now owes some of it back, the adjustment generally spreads across four tax years instead of landing all at once. Line 28 lets an applicant elect a one-year period for a positive adjustment under $50,000 rather than waiting out the four-year spread.

Line 27 asks about any remaining portion of a Section 481(a) adjustment from a prior change that still needs to be taken into account, which will not apply to a first-time depreciation correction. Line 29 asks about adjustments tied to intercompany transactions, relevant mainly to consolidated groups. For a standalone company fixing a missed depreciation deduction on property it owns outright, lines 25, 26, and the attached computation statement are where the real work happens, and 27 through 29 are usually quick nos.

Filing mechanics and where the pages actually go

An automatic change under DCN 7 gets filed in duplicate, and the two copies go to different places at different times.

The original attaches to the company's timely filed federal income tax return, extensions included, for the year of change, and this attached original does not need to be signed. A separate signed copy, sometimes called the duplicate copy, goes to the IRS in Ogden, Utah, addressed to M/S 6111, and it can go by mail, by private delivery service, or by fax to the number listed in the current instructions. That duplicate copy has to go out no earlier than the first day of the year of change and no later than the date the original is filed with the return. Missing that window has been the subject of more than one taxpayer having to request relief after the fact to fix an otherwise clean filing.

No user fee applies to an automatic change request, which is one of the clearest practical differences from the non-automatic route. The IRS does not send an acknowledgment of receipt for automatic filings either, so the Ogden mailing or its fax confirmation is the only proof you will have that the duplicate copy went out on time, and it is worth keeping.

A worked example showing what the numbers look like on paper

Say a company placed $50,000 of computer equipment into service in 2021, and through an oversight in its bookkeeping, claimed no depreciation on that equipment at all for 2021 through 2024. A new accountant catches the error while preparing the 2025 return.

One important premise before the numbers: assets placed in service in 2021 were generally eligible for 100% bonus depreciation under the Tax Cuts and Jobs Act. For this example to produce the standard MACRS calculation that follows, the company must have made a valid class-level election out of bonus depreciation for five-year property in 2021, making standard MACRS the applicable method. Without that election out, the permissible 2021 deduction would have been the full $50,000, and the Section 481(a) catch-up would be approximately $50,000, not $41,360.

This distinction matters if you are working through a real situation. If your company did not elect out of bonus depreciation for the class, the computation looks materially different, and whether the missed deduction is a method change or a missed election is a separate question with a different answer. Confirm which treatment applied before reproducing either set of numbers on an actual filing.

Computers are five-year MACRS property. Under the standard half-year convention using the 200% declining balance method, the applicable percentages for a five-year asset are 20.00%, 32.00%, 19.20%, 11.52%, and 11.52% across the first five years, with a final 5.76% in year six. Applying those percentages to the $50,000 basis for the years already passed gives $10,000 for 2021, $16,000 for 2022, $9,600 for 2023, and $5,760 for 2024. Adding those four years together produces $41,360, and because the company claimed nothing in any of those years, that entire figure is what it failed to deduct.

That $41,360 becomes the negative Section 481(a) adjustment on Part IV, line 26, supported by an attached statement laying out exactly this calculation, year by year, against the correct MACRS table. The Schedule E attachment names the equipment, states 2021 as the placed-in-service year, describes its use in the business, and confirms that no credit, grant, or subsidy was claimed with respect to it.

On the front of the form, line 1a carries DCN 7, Part III is left entirely blank because the change qualifies as automatic, and Schedule A does not get touched because this is not an overall method change. The original goes out attached to the 2025 return, and a signed duplicate goes to Ogden before or with that filing. The $41,360 reduces the company's 2025 taxable income in full, in that single year, with 2021 through 2024 left exactly as they were originally filed.

How Inkle helps

Inkle's tax team handles Form 3115 filings for US startups, including the Schedule E asset-level detail and the Section 481(a) computation. Because Inkle's accounting services maintain client financial records and asset data, the information needed to prepare the filing is typically already organized rather than assembled from scratch under deadline pressure.

Learn more about Inkle's tax filing services.

Frequently asked questions

What DCN goes on Form 3115 for missed depreciation? 

DCN 7 covers a change from an impermissible method of depreciation, including a method where no depreciation was claimed at all on eligible property, to the correct method. It goes on line 1a of the automatic change request.

Do I need to amend prior returns to fix missed depreciation? 

No, in the typical case. Under DCN 7's automatic procedure, the correction is made prospectively through the current year's Form 3115, and the missed depreciation becomes a single negative Section 481(a) adjustment deducted in the year of change rather than spread across amended filings.

Which parts of Form 3115 actually need to be completed for a depreciation catch-up? 

Under the automatic change procedure that DCN 7 uses, you complete Part I, Part II, Part IV, and the Schedule E statement. Part III applies only to non-automatic requests, which involve a user fee and a much longer process, and it does not apply here.

Where does the Section 481(a) adjustment get reported? 

On Part IV, line 26, supported by an attached statement that shows exactly how the number was computed. A negative adjustment, which is what a missed-deduction catch-up produces, is deducted in full in the single year of change rather than spread over multiple years.

Where does Form 3115 actually get sent? 

The original attaches to the company's timely filed return, including extensions, for the year of change. A signed duplicate copy goes separately to the IRS in Ogden, Utah, no earlier than the first day of the year of change and no later than the date the original is filed with the return.

Can a small business file a shorter version of the form for this? 

Yes. DCN 7 is one of the changes eligible for a reduced filing requirement for qualifying small taxpayers, which allows certain lines and schedules to be skipped. The qualifying thresholds are set by revenue procedure and change periodically, so confirm current eligibility with a preparer before relying on it. The threshold has historically been tied to a gross receipts test, set at $25 million in recent guidance for many provisions.