What Is Depreciable Basis and How Is It Calculated?

Depreciable basis is the dollar amount the IRS uses to figure your annual depreciation deductions on a business or investment asset. It starts with what you paid for the property — including sales tax, freight, and installation — and then moves up or down over the life of the asset as you make improvements, claim deductions, or take certain tax credits. The number governs three moments: the first year you place the property in service, every year you own it, and the year you sell, when it decides how much of your gain is recaptured as ordinary income.

What Depreciable Basis Is

Section 167 of the tax code allows a “reasonable allowance” for the wear, tear, and obsolescence of property used in a business or held to produce income. Section 167(c) ties the basis for depreciation to the adjusted basis under Section 1011, meaning the starting cost is modified by prior deductions, improvements, and other adjustments before any depreciation math begins.¹

The practical effect is that you spread the deduction over the asset’s recovery period under the Modified Accelerated Cost Recovery System (MACRS), reported on Form 4562. The depreciable basis drives every line of that form.²

These rules apply to tangible property — machinery, vehicles, buildings. Most intangibles follow separate regimes: off-the-shelf software is amortized straight-line over 36 months with salvage value treated as zero, and goodwill and other Section 197 intangibles are amortized over 15 years.³ What follows covers tangible property.

What Goes Into the Initial Basis

The starting point is cost.⁴ But cost in the tax code goes beyond the sticker price. Any expense needed to acquire the asset and get it ready for its intended use is folded into the basis rather than deducted as a current expense.

For equipment and other personal property, that typically means:

Sales tax, capitalized rather than deducted separately.
Freight and delivery charges to your business location.
Installation and testing charges required to make the equipment operational.

Settlement Costs on Real Estate

Real estate purchases pull in a longer list. IRS Publication 551 includes abstract of title fees, legal fees for title search and contract preparation, recording fees, transfer taxes, owner’s title insurance, survey costs, and charges for installing utility services. If you agree to cover amounts the seller owes — back taxes, sales commissions, repair charges — those go into your basis as well.⁵

Loan-related costs stay out. Points, loan origination fees, mortgage insurance premiums, loan assumption fees, lender-required appraisal fees, and credit report charges are excluded from the property’s basis.⁵ If you would have paid the cost in an all-cash purchase, it belongs in basis. If it exists only because of financing, it does not.

Mortgages Do Not Reduce Basis

Financing the purchase has no effect on the depreciable number. If you buy a building for $20,000 cash and assume an $80,000 mortgage, your basis is $100,000, the full price of the property.⁵ The same holds when you take property subject to a mortgage rather than formally assuming it. You depreciate the full cost even though you have not finished paying for the asset.

Splitting Land From Building

Land is not depreciable. When a purchase includes both a building and land, you have to allocate the price between the two, and only the building portion enters your depreciable basis.

The IRS accepts allocation by relative fair market value: multiply the total purchase price by the fair market value of the building divided by the fair market value of the whole property at the time of purchase. If fair market values are hard to pin down, assessed values from your local property tax bill can stand in.⁵ A larger building allocation produces bigger deductions now and more recapture later.

Basis for Property You Did Not Buy

Not every asset arrives through a purchase, and the rules shift accordingly.

Inherited Property

Inherited assets generally receive a stepped-up basis equal to fair market value on the date of the decedent’s death.⁶ A rental building bought decades ago for $150,000 and worth $500,000 at death enters your hands with a $500,000 basis (minus the land allocation). The prior owner’s accumulated depreciation is wiped clean.

In community property states, Section 1014(b)(6) provides an extra advantage: on the death of one spouse, both halves of community property receive the step-up, not just the decedent’s half.⁶

Gifted Property

Gifts use a carryover basis. The recipient takes the donor’s adjusted basis at the time of the gift.⁷ One exception: if the donor’s adjusted basis exceeds fair market value at the time of the gift, the recipient uses the lower fair market value for purposes of determining a loss.

Property Converted From Personal Use

Starting to use a personal asset in your business — a car, a home, a computer — sets your depreciable basis at the lesser of your adjusted basis or the fair market value on the date of conversion.⁵ A vehicle you paid $35,000 for, worth $22,000 when you start using it for business, has a depreciable basis of $22,000.

How the Basis Changes Over Time

The initial figure is a starting point. Several events push it up or down.

Improvements Increase Basis

Capital improvements add to basis; ordinary repairs do not. The IRS draws the line at three categories: a betterment that makes the property materially better, a restoration that returns it to its condition after damage or wear beyond normal maintenance, or an adaptation to a new or different use. Replacing a broken window is a repair you deduct now. Replacing the roof is a restoration that increases basis.

Depreciation, Casualties, and Credits Reduce Basis

Every depreciation deduction reduces the remaining basis, producing what the IRS calls the adjusted basis. Casualty losses and insurance reimbursements reduce it too. If storm damage to a warehouse produces $40,000 in insurance proceeds, basis drops by that $40,000 plus any deductible loss you claimed.⁸

Certain federal credits also reduce the depreciable basis of the asset that generated them. The rehabilitation credit under Section 47 reduces basis by the full amount of the credit; the energy credit under Section 48 reduces basis by 50% of the credit determined.⁹

The Allowed-or-Allowable Rule

Skipping a year of depreciation does not preserve your basis. Publication 946 is explicit: basis must be reduced by the depreciation allowed or allowable, whichever is greater.¹⁰ A missed deduction is gone, but the reduction to basis still happens.

Demolition Costs

Tearing down a structure does not produce a deduction. Under Section 280B, both the demolition expenses and any remaining basis in the demolished building must be added to the basis of the land, which is not depreciable.¹¹ Those dollars produce no depreciation at all.

When Depreciation Starts

You do not start depreciating an asset the day you buy it. Depreciation begins when the property is “placed in service,” meaning ready and available for its specific use, whether or not you are actually using it.¹⁰ Equipment sitting installed and operational, waiting for a customer order, still counts.

For property converted from personal use, the placed-in-service date is the date of conversion. That date also determines which year’s tables and rules apply.

How the Basis Feeds Into Your Deduction

Once you have the depreciable basis and a placed-in-service date, MACRS assigns the asset to a class that sets the recovery period.¹⁰

5-year property: vehicles, computers, office machinery, most general-purpose equipment.
7-year property: office furniture and fixtures, and property with no designated class life.
15-year property: land improvements such as fences, roads, sidewalks, and landscaping.
27.5-year property: residential rental buildings.
39-year property: nonresidential buildings.

Most personal property uses the 200% declining balance method, which front-loads deductions. Real property uses the straight-line method.

Section 179 Expensing

Section 179 lets you deduct the full cost of qualifying equipment in the year it is placed in service. For 2025, the maximum deduction is $2,500,000, with phase-out beginning at $4,000,000 in total qualifying purchases. The deduction cannot exceed taxable income from active business operations for the year.¹² Any Section 179 deduction reduces the asset’s depreciable basis before regular MACRS depreciation is figured on what remains.²

Bonus Depreciation

The One, Big, Beautiful Bill Act restored permanent 100% bonus depreciation for qualified property acquired after January 19, 2025.¹³ The entire depreciable basis of qualifying property can be deducted in the first year, with no dollar cap and no business-income limit. Bonus depreciation can create a net operating loss where Section 179 cannot.

Taxpayers may elect a reduced 40% rate — or 60% for certain long-production-period property and aircraft — instead of the full 100% for property placed in service during the first tax year ending after January 19, 2025.¹³

Listed Property and Mixed Use

Vehicles and certain other property prone to personal use are “listed property.” To claim MACRS accelerated depreciation, Section 179, or bonus depreciation on listed property, business use must exceed 50%.¹⁴ If business use drops to 50% or below in any year, you switch to straight-line for that year, and prior Section 179 or bonus depreciation may need to be recaptured as income. For mixed-use assets, only the business-use percentage of cost enters the depreciable basis.²

Why the Basis Still Matters When You Sell

Depreciable basis does not stop mattering when the asset stops being depreciated. Under Section 1245, when you sell depreciable personal property at a gain, the portion of the gain attributable to depreciation previously taken is recaptured as ordinary income rather than capital gain. The statute uses “recomputed basis” — the adjusted basis plus all depreciation allowed or allowable — so skipped deductions still count against you.¹⁵

For real property, Section 1250 recapture applies more narrowly, generally only to the extent depreciation exceeded what straight-line would have produced. Because most MACRS real property already uses straight-line, Section 1250 recapture is uncommon. The “unrecaptured Section 1250 gain” is still taxed at a maximum rate of 25% rather than the standard long-term capital gains rate.

Penalties for Getting the Basis Wrong

Understating or overstating basis can trigger accuracy-related penalties under Section 6662. The standard penalty is 20% of the tax underpayment attributable to negligence or a substantial understatement of income. For gross valuation misstatements, the penalty rises to 40%.¹⁶ Where the IRS finds fraud, Section 6663 imposes a penalty of 75% of the underpayment.¹⁷

Beyond penalties, deductions can be disallowed entirely without records supporting the claimed basis. Keep purchase agreements, closing statements, invoices for improvements, and documentation of insurance payouts for as long as you own the asset, and at least three years after you file the return reporting its sale.

1
Office of the Law Revision Counsel. 26 USC 167 – Depreciation
2
Internal Revenue Service. Instructions for Form 4562 (2025)
3
eCFR. 26 CFR 1.167(a)-14 – Treatment of Certain Intangible Property Excluded From Section 197
4
Office of the Law Revision Counsel. 26 USC 1012 – Basis of Property Cost
5
Internal Revenue Service. Publication 551 (12/2025), Basis of Assets
6
Office of the Law Revision Counsel. 26 USC 1014 – Basis of Property Acquired From a Decedent
7
Office of the Law Revision Counsel. 26 USC 1015 – Basis of Property Acquired by Gifts and Transfers in Trust
8
Internal Revenue Service. Publication 547 (2025), Casualties, Disasters, and Thefts
9
Internal Revenue Service. 2025 Instructions for Form 3468 – Investment Credit
10
Internal Revenue Service. Publication 946 (2025), How To Depreciate Property
11
Office of the Law Revision Counsel. 26 USC 280B – Demolition of Structures
12
Internal Revenue Service. About Form 4562, Depreciation and Amortization
13
Internal Revenue Service. Treasury, IRS Issue Guidance on the Additional First Year Depreciation Deduction Amended as Part of the One, Big, Beautiful Bill
14
Internal Revenue Service. 2025 Instructions for Form 4562
15
Office of the Law Revision Counsel. 26 USC 1245 – Gain From Dispositions of Certain Depreciable Property
16
Office of the Law Revision Counsel. 26 USC 6662 – Imposition of Accuracy-Related Penalty on Underpayments
17
Office of the Law Revision Counsel. 26 USC 6663 – Imposition of Fraud Penalty