Cost Basis of Real Estate and Home Improvements: Sale and Recapture

The cost basis of real estate and home improvements is what you’ve invested in the property for tax purposes: your original purchase price, plus capitalizable closing costs, plus every qualifying improvement you make while you own it, minus reductions like depreciation and insurance reimbursements. That single number decides how much of your sale proceeds the IRS treats as taxable gain. A single filer can exclude up to $250,000 of gain on a primary residence, and a married couple filing jointly can exclude up to $500,000, but the exclusion only applies to the gain calculated above your adjusted basis.¹ Undercount your basis and you overpay; overcount it and you risk a 20% accuracy-related penalty on the underpaid tax.²

What Goes Into Your Starting Basis

Basis begins with the purchase price, then absorbs certain settlement fees you paid at closing.³ Most buyers overlook these because they feel like transaction expenses, but the IRS treats them as part of what you paid for the property itself.

Closing costs you can add to basis include abstract fees, title searches, owner’s title insurance, and recording fees; any state or local transfer taxes; legal fees for preparing the sales contract and deed; survey charges paid at closing; and charges to connect utility services to the property.³ All of these show up on your Closing Disclosure (or the older HUD-1 settlement statement). Keep that document permanently. It’s the cleanest record of your starting basis you’ll ever have.

Not every line on the settlement statement qualifies. Loan-related charges — mortgage insurance premiums, credit report fees, and points paid to reduce your interest rate — don’t add to basis. Those are either deductible as interest or simply non-capitalizable. The dividing line is what the fee was for: acquiring the property increases basis, financing the purchase does not.

Improvements That Increase Your Basis

Once you own the home, capital improvements are how basis grows over time. The IRS defines an improvement as something that adds value to your home, extends its useful life, or adapts it to a different use.⁴ The cost of each qualifying project gets added to basis dollar for dollar.

Common examples include:

Additions like a new bedroom, bathroom, deck, garage, or finished basement
Systems work such as a new heating system, central air conditioning, ductwork, plumbing, wiring, or a security system
Exterior work: a new roof, new siding, storm windows, or added insulation
Grounds improvements including landscaping, a paved driveway, fencing, a retaining wall, or a swimming pool

The common thread is permanence. Replacing a whole HVAC system qualifies because the new unit serves the house for years. So does running new plumbing lines or replacing every window in the home.⁴

Repairs Don’t Count

Fixing a leaky faucet, patching drywall, or repainting a room does not increase your basis. These are repairs. They keep the home in its current condition rather than making it meaningfully better. Over a long ownership period, that distinction is enormous. Spend $80,000 on genuine improvements over 20 years and you reduce your taxable gain by $80,000. Spend the same $80,000 on repairs and you get nothing at sale.

Most mistakes happen in the gray area. Replacing a single broken windowpane is a repair. Replacing every window with energy-efficient models is an improvement. Patching a section of roof is a repair. Putting on an entirely new roof is an improvement. When you’re unsure, ask whether the project restored something to its prior condition or made it better and longer-lasting.

One exception cuts the other way. If a casualty like a storm or fire damages your home and you spend money restoring it, those restoration costs get capitalized into basis even though the work looks like a repair. That’s because you already reduced basis by the insurance reimbursement and any deductible loss, and the restoration returns the property to its pre-damage condition.⁵

What Decreases Your Basis

Basis doesn’t only go up. Several events push it down, and missing them is one of the most common ways homeowners understate their gain at sale. Publication 551 lists every category.³

Depreciation on Rental or Business Use

If you use part of your home as a rental or claim a home-office deduction, you’re required to depreciate the business-use portion of the property each year. Depreciation reduces basis whether you actually claimed it or not. The IRS reduces basis by the amount “allowable,” not just the amount “allowed.”⁶ A homeowner entitled to $3,000 a year in depreciation who never claimed it still sees basis drop by that $3,000 each year.

Casualty Reimbursements

When a casualty damages the home, decrease basis by any insurance reimbursement you receive and by any deductible loss you claim.⁵ Restoration spending after that comes back onto basis, as noted above.

Residential Energy Credits

Claiming a residential energy credit for improvements like solar panels or energy-efficient windows requires you to reduce basis by the credit amount.³ You still get the full improvement cost added to basis first, then subtract the credit. Install a $25,000 solar system and claim a $7,500 credit, and your net basis increase is $17,500. A utility subsidy for energy conservation works similarly: you can exclude it from income, but you must reduce basis by the same amount.

Easements and Rebates

Granting a permanent easement — say, letting a utility company run power lines across your land — is treated as a partial sale. The payment reduces the basis of the affected portion of your property, and any payment above that portion’s basis is a recognized gain.³ Manufacturer rebates tied to a property purchase, like a builder incentive or appliance rebate bundled into a new-home deal, also reduce basis because the IRS treats them as adjustments to the sales price.

How Basis Plays Out at Sale

Your gain equals the selling price, minus selling expenses (real estate commissions, advertising, legal fees, any loan charges you paid that would normally be the buyer’s responsibility), minus your adjusted basis.⁴ To use the Section 121 exclusion, you must have owned and used the home as your principal residence for at least two of the five years before the sale, and you can only use the exclusion once every two years.¹ A surviving spouse who sells within two years of their spouse’s death can still use the $500,000 exclusion while filing as single.

A concrete example shows why tracking improvements matters. You bought a home for $300,000, spent $75,000 on qualifying improvements over 15 years, and sell for $700,000 with $45,000 in selling expenses. Adjusted basis is $375,000, amount realized is $655,000, gain is $280,000. A single filer owes tax on $30,000, the amount above the $250,000 exclusion. Without documentation for those improvements, gain would be $355,000, and $105,000 would be taxable. That difference in record-keeping can easily mean $15,000 or more in federal tax.

A boundary worth knowing: if you sell your primary residence for less than your adjusted basis, you cannot deduct the loss on your federal return.⁷ Section 121 shelters gains only. All those capitalized improvements can shrink a gain to zero, but they cannot create a deductible loss on a personal residence.

If you used the property for something other than your principal residence during part of your ownership — renting it out for three years before moving in, for instance — a portion of the gain tied to that nonqualified use period cannot be excluded. The IRS calculates this by dividing the total time of nonqualified use by the total time you owned the property, and periods before January 1, 2009, are excluded from the calculation.¹

Inherited, Gifted, and Exchanged Property

Basis works differently when you didn’t buy the property yourself.

Inherited Property

Inherit real estate and the tax code generally resets basis to the property’s fair market value on the date the previous owner died.⁸ This step-up in basis can erase decades of appreciation. A parent who bought a house for $80,000 in 1985 that’s worth $550,000 at their death leaves an heir with a basis of $550,000. A sale shortly after at that price produces no taxable gain. In community property states, both halves of community property receive a stepped-up basis when one spouse dies, not just the deceased spouse’s half.⁹

Gifted Property

Property received as a gift is different. Instead of a step-up, you generally take over the donor’s adjusted basis: whatever they paid, plus their improvements, minus their depreciation and other reductions.¹⁰ A parent gifts you a home they bought for $150,000 and improved by $30,000, and your basis is $180,000 regardless of the home’s current market value.

A special rule applies when the donor’s adjusted basis is higher than the property’s fair market value at the time of the gift. You use fair market value as your basis for calculating any loss, and the donor’s basis for calculating any gain. If the selling price falls between those two numbers, you have no gain and no loss.¹⁰

1031 Like-Kind Exchanges

Investors who swap one investment property for another under Section 1031 defer capital gains tax but carry the old basis forward. Basis in the replacement property equals the basis of the property given up, decreased by any cash received and increased by any gain recognized on the exchange.¹¹ A liability assumed by the other party counts as money received. Over a chain of exchanges, basis can drop far below market value; an investor who exchanges through three properties over 25 years might end with a $1.5 million property and a $200,000 carryover basis. The deferred gain stays embedded in that basis until a taxable sale occurs.

Depreciation Recapture When You Sell

If you claimed depreciation on rental property or a home office, the gain attributable to that depreciation is taxed at a maximum rate of 25% as unrecaptured Section 1250 gain, even when the rest of your gain qualifies for long-term capital gains rates of 0%, 15%, or 20%.¹² Recapture on depreciation taken after May 6, 1997, cannot be sheltered by the Section 121 exclusion.⁶

Rent out your home for five years, claim $40,000 in depreciation, and even if the remaining gain fits inside the $250,000 exclusion, that $40,000 is taxed separately at up to 25%. Homeowners who convert a rental back to a primary residence sometimes assume the exclusion wipes out everything. It doesn’t, and the recapture bill often surprises them.

Records You Need to Keep

Keep records related to basis until the statute of limitations expires for the year you sell the property, which generally means at least three years after you file the return reporting the sale.¹³ For a 1031 exchange, keep records for both the old and new properties until the limitations period expires on the return for the year you sell the final replacement property.

For a typical homeowner, the essential documents are:

Your Closing Disclosure or HUD-1, which fixes the purchase price and capitalizable closing costs
Improvement invoices and receipts showing the date, nature of the work, and total paid to each contractor or supplier
Insurance claim records for any casualty reimbursements that reduced basis
Depreciation schedules if the property was ever rented or used for a home office
Any Form 5695 filed for residential energy credits, showing the credit amount that reduced basis

Digital storage is fine. The IRS doesn’t require paper originals. The real risk is that 15 or 20 years pass between purchase and sale and the receipts vanish. Without proof, the IRS can disallow basis additions, which increases your taxable gain by whatever you can’t substantiate. Filing each contractor invoice the month the work is completed is far easier than reconstructing the record at sale time.

1
Office of the Law Revision Counsel. 26 USC 121 – Exclusion of Gain From Sale of Principal Residence
2
Internal Revenue Service. Accuracy-Related Penalty
3
Internal Revenue Service. Publication 551 – Basis of Assets
4
Internal Revenue Service. Publication 523 – Selling Your Home
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Internal Revenue Service. Publication 547 – Casualties, Disasters, and Thefts
6
Internal Revenue Service. Property (Basis, Sale of Home, Etc.) 5
7
Internal Revenue Service. Capital Gains, Losses, and Sale of Home
8
Internal Revenue Service. Gifts and Inheritances
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Internal Revenue Service. Publication 555 – Community Property
10
Office of the Law Revision Counsel. 26 USC 1015 – Basis of Property Acquired by Gifts and Transfers in Trust
11
Office of the Law Revision Counsel. 26 USC 1031 – Exchange of Real Property Held for Productive Use or Investment
12
Internal Revenue Service. Topic No. 409 – Capital Gains and Losses
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Internal Revenue Service. How Long Should I Keep Records