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Capital Improvements and Capital Gains Deductions: How to Reduce Your Tax

By RE Tax Calc Editorial · Published October 22, 2026

Every dollar you spend improving your property can permanently reduce your capital gains tax bill when you sell — but only if you track it correctly and classify it as a capital improvement rather than a repair. This guide explains how improvements work under IRC §1016, which costs qualify, and how much you can save.

Illustration for Capital Improvements and Capital Gains
Quick Answer Capital improvements increase your adjusted basis under IRC §1016(a)(1), which reduces your taxable gain dollar-for-dollar when you sell. A $20,000 kitchen remodel added to basis can save $3,000–$4,000 in federal capital gains tax (at the 15% long-term rate), plus any applicable state tax and reduced exposure to the 3.8% NIIT. Repairs, by contrast, do not add to basis.
IRC §1016 — Adjustments to basis: §1016(a)(1) requires that basis be increased by the cost of improvements, betterments, and restorations to property. Treas. Reg. §1.263(a)-3 (the tangible property regulations) provides a framework — the BAR test — for distinguishing capital improvements from deductible repairs: Betterment (adds value or fixes a pre-existing defect), Adaptation (adapts to a new use), or Restoration (restores a unit of property from a casualty or retired component).

Why improvements reduce capital gains tax

Your capital gains tax is calculated on your gain, which equals your amount realized (sale price minus selling costs) minus your adjusted basis. Adjusted basis starts at your original purchase price and is then:

Because gain = amount realized − adjusted basis, a higher basis means a lower gain and therefore lower tax. Every $1 of qualifying improvement adds $1 to basis, potentially saving you $0.15–$0.238 (or more, at higher state rates) per dollar of improvement cost — at the time of sale.

Capital improvements vs. repairs: the distinction

The IRS tangible property regulations (Treas. Reg. §1.263(a)-3, effective for tax years beginning January 1, 2014) use a "unit of property" analysis and the BAR test to distinguish improvements from repairs:

Costs that ARE capital improvements (add to basis)

Costs that are repairs (NOT added to basis)

Gray areas: The repair vs. improvement distinction can be complex. A single plumbing fix is a repair; replacing the entire plumbing system is an improvement. An HVAC tune-up is a repair; a full HVAC system replacement is an improvement. When in doubt, keep all documentation and consult a tax professional or CPA.

How much can you save?

The tax savings from a capital improvement depend on your long-term capital gains tax rate (0%, 15%, or 20%) and whether the 3.8% NIIT applies. Here is a savings table for a qualifying improvement:

Improvement Cost At 15% LT rate At 20% + 3.8% NIIT
$5,000 (e.g., new deck) $750 $1,190
$20,000 (kitchen remodel) $3,000 $4,760
$35,000 (roof + HVAC) $5,250 $8,330
$80,000 (addition) $12,000 $19,040

Federal capital gains tax savings only. State capital gains tax would add additional savings. Rates shown are federal long-term capital gains rates; these thresholds adjust annually.

Worked example: $20,000 kitchen remodel

Suppose you purchased a rental property in 2015 for $350,000 and in 2020 spent $20,000 on a full kitchen remodel (new cabinets, countertops, sink, backsplash). You sell in 2026 for $520,000 with $18,000 in selling costs and $87,273 of accumulated MACRS depreciation.

Without tracking the improvement:

With the $20,000 kitchen remodel tracked:

At the 20% + 3.8% NIIT rate, the same $20,000 improvement would save $4,760. And if the taxpayer also owes state capital gains tax, the total savings would be even greater.

Rental property: improvements can also generate depreciation deductions

For rental properties, a capital improvement provides a double benefit. Not only does it increase your basis (reducing future gain), it is also depreciable over its MACRS recovery period — generating annual deductions that offset rental income now:

Cost segregation studies can reclassify structural components into shorter-lived property classes, accelerating depreciation deductions further. See our Cost Segregation Calculator.

Documentation you must keep

The IRS requires substantiation for all basis adjustments. For each capital improvement, keep:

Keep these records for at least 3 years after the tax year in which you sell the property. If you claim a loss, keep records for 7 years. The IRS can assert a 6-year limitation period if you omit income equal to 25% or more of gross income. Many tax professionals recommend keeping improvement records permanently for real estate.

Pre-sale improvements: strategy vs. deduction

Some property owners make improvements immediately before a sale to increase the listing price. While these improvements also increase basis, the timing matters:

Frequently asked questions

Do capital improvements reduce capital gains tax?

Yes. Capital improvements increase your adjusted basis under IRC §1016(a)(1). A higher basis means a smaller gain when you sell, which directly reduces capital gains tax. For example, a $20,000 kitchen remodel added to basis saves approximately $3,000–$4,000 in federal capital gains tax for a taxpayer in the 15% long-term capital gains bracket (plus any applicable state tax).

What is the difference between a capital improvement and a repair?

A capital improvement adds value, extends the useful life, or adapts the property to a new use. Repairs merely maintain the property in its current condition. Improvements are added to basis; repairs are expensed (deducted as ordinary expense for rentals) but do not increase basis. The IRS tangible property regulations under Treas. Reg. §1.263(a)-3 provide a detailed framework including the BAR test (Betterment, Adaptation, Restoration).

Do I need receipts for capital improvements?

Yes. The IRS requires substantiation for all basis additions. You should keep original receipts, contracts, permits, and cancelled checks for every capital improvement, as well as a running basis log for each property. Records should be kept for at least 3 years after the tax year you sell the property (the statute of limitations for assessment), and potentially longer if the gain is large.

Can I deduct improvements in the year I make them?

Not as a capital gains deduction in the year spent — improvements are added to basis and benefit you when you sell. For rental property, some improvements may be depreciated over the applicable MACRS life (27.5 or 39 years), which gives annual deductions offsetting ordinary rental income. Some shorter-lived components may qualify for bonus depreciation or Section 179 expensing under current law.

What improvements qualify for basis addition?

Qualifying improvements include room additions, new roof, HVAC replacement, kitchen remodels, bathroom additions, new plumbing or electrical systems, landscaping (permanent), driveways, fences, and patios. Non-qualifying (repair) items include painting, fixing leaky faucets, replacing broken windows, and routine cleaning or maintenance.

Educational information and estimates only. Not tax advice. Tax rules change and vary by situation; consult a qualified tax professional before acting.

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