What Is Cost Basis in Real Estate: Adjustments, Sale, and Reporting

Cost basis in real estate is the dollar figure the IRS treats as your investment in a property: what you paid to acquire it, adjusted over time for improvements, depreciation, and certain other events. When you sell, you subtract this adjusted basis from your net sale proceeds to determine your taxable gain. Get the number right and you pay tax only on real profit. Get it wrong and you either overpay or face accuracy penalties on the shortfall.

What Your Starting Basis Includes at Purchase

Your initial basis is the purchase price on the sales contract plus specific closing costs. IRS Publication 551 draws the line by asking what each fee is for: costs tied to acquiring the property add to basis; costs tied to getting a loan do not.¹

Closing costs that add to basis include title search charges, abstract fees, and owner’s title insurance; attorney fees for preparing the deed and sales contract; county recording fees; state and local transfer taxes; survey costs; and utility hookup charges.

Loan-related costs sit on the other side of the line. Discount points, loan origination fees, mortgage insurance premiums, and loan assumption fees do not add to basis.¹ The logic: those fees exist only because you borrowed. A cash buyer wouldn’t owe them, so they aren’t part of the investment in the property itself.

One wrinkle worth knowing. If the seller agrees to cover some of your closing costs and the sales price is bumped up to compensate, your basis reflects the higher contract price. What matters is the number on the settlement statement, not who actually wrote the checks at closing.

Improvements That Raise Basis, Repairs That Don’t

Money you spend after purchase gets added to basis only when the work qualifies as a capital improvement. The IRS looks for work that adds value, extends the property’s useful life, or adapts it to a new purpose.¹ Publication 523 gives a broad list of qualifying work:²

Additions such as bedrooms, bathrooms, garages, decks, and porches
Major systems including central air, furnaces, ductwork, security systems, and wiring
Exterior work such as a new roof, siding, storm windows, and insulation
Interior upgrades like kitchen modernization, built-in appliances, wall-to-wall carpeting, and fireplaces
Grounds work including landscaping, driveways, walkways, fences, retaining walls, and swimming pools
Plumbing improvements such as septic systems, water heaters, water softeners, and filtration

Professional fees tied to a capital improvement travel with the improvement. Architect fees for a home addition, engineering fees for a structural renovation, permit costs, and contractor charges all combine into the improvement’s total and get added to basis together.

Routine repairs and maintenance do not qualify. Painting walls, fixing leaky faucets, patching cracks, and replacing broken hardware keep the property in its current condition rather than making it better. The practical test: did the work restore something that was broken, or create something new? Restoration is a repair. Creation is an improvement.²

What Lowers Your Basis

Several events push basis down. Miss any of them and you’ll understate your gain at sale, which invites penalties.

Depreciation

If the property is used for business or rental, you claim depreciation each year for wear and tear on the building. Those annual deductions must come off your basis whether or not you actually claimed them. The IRS reduces basis by depreciation “allowed or allowable,” so skipping the deduction on a return doesn’t preserve basis.³ After several years of rental depreciation, basis can be well below what you originally paid.

Insurance Payouts and Casualty Losses

Insurance reimbursements for property damage reduce basis, and any deductible casualty loss you claimed comes off as well.⁴ If a storm damages the roof and insurance pays $15,000, basis drops by that amount even if you spend the money rebuilding.

Residential Energy Credits

Tax credits for energy-efficient improvements reduce the basis increase from that same improvement. Publication 551 states the rule directly: the increase in basis “will be reduced by the amount of the allowed credit.”¹ Spend $10,000 on a solar installation and take a $3,000 credit, and only $7,000 gets added to basis. Subsidies from public utilities for energy conservation follow the same rule.

Easement Payments

Selling a conservation easement or similar property right reduces basis by the payment amount. When the payment exceeds your adjusted basis, basis goes to zero and the excess is a taxable gain.

How You Got the Property Changes the Starting Number

The rules above assume you bought the property. When property comes to you another way, the starting basis is calculated differently.

Inherited Property: Step-Up in Basis

Inheriting real estate comes with a significant tax advantage. Your basis becomes the property’s fair market value on the date of death, not the deceased owner’s original cost.⁵ If a parent bought a home for $80,000 in 1985 that was worth $450,000 at death, your basis is $450,000. All the appreciation during the parent’s life is wiped out for capital gains purposes.

The executor can elect an alternate valuation date six months after death when doing so reduces both the gross estate and the total estate tax. If that election is made, your stepped-up basis uses the six-month value.⁶ The election is irrevocable once filed, so understand its effect on basis before it’s made.

Gifted Property: Carryover Basis

Gifts work very differently. When someone gives you real estate, you generally take over the donor’s adjusted basis at the time of the gift, along with their improvement and depreciation history.⁷

A special rule kicks in when the property’s fair market value at the time of the gift is lower than the donor’s basis. If you later sell at a loss, your basis for the loss calculation is the fair market value on the gift date, not the donor’s higher basis. That prevents shifting unrealized losses from one person to another.⁷ Getting carryover basis right requires the donor’s records: original price, improvements, and any depreciation claimed.

Converting a Home to Rental

When you switch a home to rental use, your depreciable basis is the lesser of fair market value on the conversion date or your adjusted basis at that time.⁸ The rule matters most when values have dropped. Pay $350,000 for a home that’s worth $280,000 at conversion, and your depreciable basis starts at $280,000. If the home appreciated to $400,000 instead, depreciable basis stays at your original adjusted basis.

Like-Kind Exchanges Under Section 1031

A Section 1031 exchange lets you swap one investment or business property for another and defer the capital gains tax. Basis doesn’t reset. The basis from the property you gave up carries over to the replacement, preserving the deferred gain for later.⁹ The exchange must involve real property held for business or investment; personal residences and property held for resale don’t qualify.¹⁰ Cash or non-qualifying property received in the deal (called “boot”) is immediately taxable and adjusts your basis in the replacement.

How Basis Plays Out at Sale

The core calculation is simple. Subtract your adjusted basis from the amount realized to find your gain or loss.¹¹ The “amount realized” isn’t just the sale price. You subtract selling expenses first: real estate commissions, advertising costs, legal fees, and transfer taxes all reduce the amount realized before basis is applied.²

The Section 121 Exclusion for a Primary Residence

If the property was your main home, you may exclude up to $250,000 of gain ($500,000 for married filing jointly). You must have owned and used it as your primary residence for at least two of the five years before sale, and you can only claim the exclusion once every two years.¹²

This is where careful basis tracking pays off. Buy a home for $300,000, add $50,000 in documented improvements, and sell for $600,000: your gain is $250,000 against an adjusted basis of $350,000, and a single filer can exclude the entire amount. Miss the improvement records and you show a $300,000 gain instead, with $50,000 needlessly taxable.

Depreciation Recapture on Rentals

If you claimed depreciation on a rental or business property, a gain at sale triggers depreciation recapture. The portion of gain attributable to prior depreciation is taxed at a maximum rate of 25%, regardless of your regular bracket.¹³ Any remaining gain is taxed at long-term capital gains rates of 0%, 15%, or 20%, depending on income. Because recapture is based on depreciation you were entitled to claim, skipping the deduction during ownership doesn’t avoid the recapture bill later.

Reporting, Penalties, and Records

Real estate sales go on Form 8949, which feeds into Schedule D. Column (e) is where your cost or adjusted basis goes. If a Form 1099-B or 1099-S reports a different figure, you correct it with adjustment codes in column (f).¹⁴

Wrong numbers cost real money. An understated basis inflates your gain and you overpay. An overstated basis understates the gain and invites penalties: a 20% accuracy-related penalty for negligence or substantial understatement, doubling to 40% for a significant valuation misstatement.¹⁵ Intentional fraud carries a 75% penalty.

The foundation of your records is the closing disclosure, or a HUD-1 settlement statement for purchases before October 2015. Beyond that, keep receipts, invoices, contractor agreements, permit records, and any professional fees for every improvement. For inherited property, a professional appraisal establishing fair market value on the date of death (or the alternate valuation date) is the key document; if an estate tax return was filed, the basis reported there caps what you can claim.

The IRS says to keep property records until the statute of limitations runs on the return for the year of disposition.¹⁶ In practice, that means holding these documents for the entire time you own the property plus at least three years after filing the return for the year of sale. For rental property with depreciation recapture in play, keep them longer. A missing $12,000 receipt for a roof replacement can mean paying tax on $12,000 that was never really profit.

1
Internal Revenue Service. Publication 551 (12/2025), Basis of Assets
2
Internal Revenue Service. Publication 523 (2025), Selling Your Home
3
Office of the Law Revision Counsel. 26 USC 167 – Depreciation
4
Internal Revenue Service. Publication 547 (2025), Casualties, Disasters, and Thefts
5
Office of the Law Revision Counsel. 26 USC 1014 – Basis of Property Acquired From a Decedent
6
Office of the Law Revision Counsel. 26 US Code 2032 – Alternate Valuation
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 527 (2025), Residential Rental Property
9
Internal Revenue Service. Like-Kind Exchanges Under IRC Section 1031
10
Office of the Law Revision Counsel. 26 US Code 1031 – Exchange of Real Property Held for Productive Use in a Trade or Business or for Investment
11
Office of the Law Revision Counsel. 26 USC 1001 – Determination of Amount of and Recognition of Gain or Loss
12
Office of the Law Revision Counsel. 26 USC 121 – Exclusion of Gain From Sale of Principal Residence
13
Internal Revenue Service. Topic No. 409, Capital Gains and Losses
14
Internal Revenue Service. 2025 Instructions for Form 8949 – Sales and Other Dispositions of Capital Assets
15
Internal Revenue Service. Publication 550 – Investment Income and Expenses
16
Internal Revenue Service. Topic No. 305, Recordkeeping