Real Estate Tax Calc
The problem: missed depreciation
Many landlords fail to claim depreciation correctly — or at all — in early years. You generally can't amend returns older than three years to fix it. And skipping the deduction doesn't help at sale: the IRS taxes recapture on depreciation "allowed or allowable," meaning you still owe it on what you could have taken.
The fix: Form 3115
IRS Form 3115 (Application for Change in Accounting Method) lets you make an automatic accounting method change to correct improper depreciation. The cumulative amount you should have taken but didn't becomes a Section 481(a) adjustment — a single deduction taken all at once in the year you file.
How to use it
Your tax professional files Form 3115 with your current-year return and sends a copy to the IRS national office. You calculate the total depreciation missed from the placed-in-service date through the correction year and claim the full shortfall as a current-year deduction. The adjustment is ordinary — it offsets ordinary income just as the annual deductions would have.
Why not simply amend your returns instead
Amending is limited and often unavailable. You can generally amend a return only within three years of filing (or two years from paying the tax, if later), so depreciation missed four, five, or ten years ago is beyond reach through amendment. Form 3115 has no such lookback limit — the Section 481(a) adjustment sweeps in all the missed depreciation, no matter how many years back it goes, in a single current-year deduction.
There is also a technical reason the IRS prefers Form 3115 here. Failing to claim depreciation you were entitled to for two or more consecutive years is treated as having adopted an impermissible method of accounting. Correcting a method of accounting is done through Form 3115, not by amending — which is why the change is usually available as an automatic consent request rather than requiring advance IRS approval.
The two most common change numbers
Most rental catch-ups fall under a designated automatic change number (DCN) on Form 3115. The frequently used codes are DCN 7 (change in depreciation method, recovery period, or convention — for example, you depreciated a residential rental over 39 years instead of 27.5) and DCN 107 (a change from an impermissible to a permissible method for depreciable property — for example, you claimed no depreciation at all). Because these are automatic changes, there is generally no user fee, but the form and its computations are detailed.
The mechanics are unforgiving of errors, so this is a filing most landlords hand to a CPA or enrolled agent. The preparer computes the correct depreciation for every year from the placed-in-service date, compares it to what you actually claimed, and reports the cumulative difference as the Section 481(a) adjustment on the current return.
A worked example
Suppose you placed a $275,000 residential rental (building basis $220,000) in service in 2018 and never claimed depreciation. Correct annual depreciation is about $8,000 ($220,000 ÷ 27.5). By your 2025 return, you should have claimed roughly 8 years × $8,000 ≈ $60,000 (adjusting the first and last years for the mid-month convention).
Filing Form 3115 with your 2025 return lets you claim a $60,000 Section 481(a) deduction all at once in 2025, then resume the normal ~$8,000 annual deduction going forward. In a 24% bracket, that one-year catch-up is worth about $14,400 in tax savings — money you would otherwise have lost entirely, since you would still owe recapture on the $60,000 at sale whether or not you ever deducted it.
A negative vs. positive adjustment
Most catch-ups produce a negative (favorable) Section 481(a) adjustment — a deduction — because you under-claimed depreciation. The full negative adjustment is taken in the year of change. If instead you over-claimed depreciation (a positive adjustment increasing income), the rules let you spread that income over four years, softening the hit. Either way, Form 3115 is the vehicle; only the direction and timing of the adjustment differ.
Note that the adjustment is ordinary in character. A favorable adjustment offsets ordinary income (including wages, if passive-loss rules permit) rather than capital gain, which is generally advantageous because ordinary rates are higher than long-term capital gains rates.
Passive activity limits still apply to the catch-up
A large Section 481(a) catch-up deduction is still subject to the passive activity loss rules. If your rental losses are passive and you have no passive income to absorb the deduction, the catch-up may be suspended and carried forward rather than deducted immediately — releasing when you have passive income or when you sell the property in a fully taxable disposition.
Investors who actively participate and are under the income phase-out may use up to $25,000 of rental losses against ordinary income; real estate professionals and qualifying short-term-rental operators face no such cap. Because a big one-year catch-up can exceed what you can currently use, some taxpayers time the Form 3115 filing for a year with offsetting income. Discuss the timing with your advisor.
Common mistakes and cautions
Watch for these: (1) trying to fix old missed depreciation by amending instead of filing Form 3115 — amendment does not work for a method change and is time-barred beyond three years; (2) forgetting that recapture at sale is based on depreciation allowed or allowable, so skipping depreciation never avoids the tax — it only forfeits the deduction; (3) missing the requirement to file two copies (one with the return, one with the IRS) within the required window; and (4) miscomputing the cumulative adjustment by ignoring the mid-month convention or the correct recovery period. Given the complexity and the dollars involved, professional preparation is strongly advised.
When you can and cannot use Form 3115
Form 3115 fixes an impermissible method of accounting — which is what claiming the wrong amount of depreciation (or none) for two or more consecutive years is treated as. But it is not a cure-all. If you simply made a math error or omitted depreciation in only the most recent year, that is not yet an established method, and the fix is to amend that single return rather than file Form 3115. The method-change route becomes available once the error has been repeated for two or more years.
Also, a change in the use of the property (converting a personal residence to a rental, for example) is generally not a Form 3115 situation — it simply establishes a new depreciation schedule going forward. And you cannot use Form 3115 to change a valid election you made, such as an election out of bonus depreciation. The form addresses genuinely impermissible methods, not second-guessing choices that were permissible when made.
Timing the filing for maximum benefit
Because a favorable Section 481(a) adjustment lands entirely in the year you file, when you file matters. Filing in a high-income year magnifies the value of the deduction — but only if you can actually use it. For a passive investor with no passive income, a large catch-up may be suspended and carried forward, so the immediate cash-tax benefit could be muted regardless of the year.
Some owners deliberately time the Form 3115 filing to coincide with a year they will have offsetting income — for example, the year they plan to sell the property (when suspended passive losses release and the gain is realized) or a year of unusually high other income. Others file as soon as they discover the error to lock in the correction. There is no single right answer; the optimal timing depends on your bracket, your passive-income picture, and your plans for the property.
Interaction with a later sale
A frequent motivation for filing Form 3115 is an impending sale. Since recapture at sale is computed on depreciation allowed or allowable, a seller who never claimed depreciation faces the worst outcome: full recapture with no deductions ever taken. Filing Form 3115 before the sale lets you claim the entire missed deduction as a current-year Section 481(a) adjustment, so you at least receive the tax benefit you were entitled to — turning a pure loss into a wash or better.
Practically, this means an investor who realizes at closing that they never depreciated should talk to a CPA about a Form 3115 for the year of sale (or an earlier year) rather than resigning themselves to recapture on deductions they never took. The catch-up deduction and the recapture are both ordinary in nature, but capturing the deduction is far better than forfeiting it.
Frequently asked questions
Can I amend old returns to catch up depreciation?
Only for the last three years. For older missed depreciation, Form 3115 is the proper remedy.
Does a Form 3115 catch-up reduce future recapture?
No — recapture at sale is based on depreciation allowed or allowable. The 3115 simply lets you take the deductions you were entitled to.
Is there a limit on how far back Form 3115 can reach?
No. Unlike amending a return (limited to about three years), the Section 481(a) adjustment on Form 3115 captures all missed depreciation back to the placed-in-service date, in a single current-year deduction.
Is there a fee to file Form 3115 for a depreciation catch-up?
Most rental depreciation corrections qualify as automatic accounting-method changes (commonly DCN 7 or DCN 107), which generally carry no IRS user fee. The cost is usually the preparer's time, since the computations are detailed.
Can I take the whole catch-up deduction this year?
A favorable (negative) Section 481(a) adjustment is taken entirely in the year of change, but the passive activity loss rules may limit how much you can actually use now. Any excess passive loss carries forward and releases against future passive income or at sale.
Sources
Educational information and estimates only. Not tax advice. Tax rules change and vary by situation; consult a qualified tax professional before acting.