Capital Gains Tax on Selling an Idaho House: What the 5.3% Rate Means for Your Sale

Published November 3, 2026

Idaho has one income tax rate: 5.3%. Capital gains are not taxed separately or at a lower rate the way they are at the federal level. When you sell your house, any gain above what federal law excludes gets added to your Idaho taxable income and taxed at the same flat rate as wages.

For most primary residence sellers, that means nothing. The federal exclusion is large enough to cover the entire gain on a typical Idaho sale. For sellers with substantial appreciation, investment properties, or homes bought in the Treasure Valley in the 2010s and now selling in a very different market, the numbers warrant a closer look.

Here is what actually applies in Idaho, starting from federal law and working down to state.

The Federal Foundation: What IRC 121 Covers

Section 121 of the Internal Revenue Code lets you exclude up to $250,000 of capital gain from the sale of your primary residence if you are single, or $500,000 if you are married filing jointly. You need to have owned and lived in the home as your primary residence for at least two of the five years before the sale. You can only use the exclusion once every two years.

Idaho conforms to the federal tax code on this point. If the gain is excluded at the federal level, it does not appear in your Idaho taxable income either. The exclusion is not capped by home price; what matters is the size of your gain, not the sale price.

On a $480,000 Boise home purchased in 2017 for $280,000, the gross gain is $200,000. For a single filer, the $250,000 exclusion covers the entire amount. Federal tax: zero. Idaho tax: zero.

The exclusion does not apply to investment properties, vacation homes, or houses where you have not met the two-of-five-year requirement. If you only lived there 18 of the 24 months required, you get a proportional exclusion, not a full one.

Idaho’s Rate and What It Applies To

Idaho taxes capital gains as ordinary income. There is no separate capital gains bracket the way there is at the federal level. Under House Bill 40, enacted in March 2025, Idaho’s flat income tax rate is 5.3% for 2025 and forward.

If your gain exceeds what IRC 121 covers, Idaho taxes the remainder at 5.3%. The gain retains its federal character (long-term or short-term), but Idaho applies the same flat rate regardless of how long you held the property.

The 60% Deduction Most Idaho Sellers Miss

Idaho Code 63-3022H allows a deduction equal to 60% of capital gain net income from the sale of qualified property. For Idaho real estate, qualified property means real property with Idaho situs held for at least 12 months. This deduction is separate from and stacks on top of the IRC 121 exclusion.

In practice, any taxable capital gain on Idaho real property held more than a year gets reduced by 60% before Idaho taxes it. The remaining 40% is taxed at 5.3%, producing an effective Idaho rate of 2.12% on qualifying long-term gains.

The deduction does not apply to property depreciated under IRC Section 1245 (personal property and certain equipment), but it does apply to residential and commercial real estate held 12 months or longer. To claim it, you complete Form CG, Idaho’s capital gains deduction worksheet, and attach it to your Idaho Form 40.

Most national content describing Idaho’s rules ignores IC 63-3022H or describes Idaho as taxing capital gains at a flat 5.3% without noting the deduction. If your accountant’s estimate does not account for Form CG, ask about it before you close.

A Worked Example: Boise House Bought in 2012

A married couple purchased a Boise home in 2012 for $225,000. They sell in late 2026 for $825,000. They have lived there continuously and meet the two-of-five-year rule. Their gross capital gain is $600,000.

On a $600,000 gross gain, the effective Idaho state tax is $2,120. The federal tax on the same $100,000 taxable gain is calculated separately at 0%, 15%, or 20% depending on your income level.

What Counts as Your Basis

The gain is sale price minus adjusted basis. Your adjusted basis is more than the original purchase price. It includes the original purchase price, closing costs paid at purchase (title insurance, recording fees, inspection fees), and capital improvements during ownership: a new roof, an addition, an HVAC replacement. Maintenance and repairs do not count.

Every dollar of verifiable capital improvement raises your basis and reduces your taxable gain. Keep receipts and permits for any work done to the house. Recording fees in Ada and Canyon Counties are set by IC 31-3205 and are modest, but they add to basis on both the purchase and sale.

Short-term gains on property held less than one year are taxed at ordinary income rates federally and at 5.3% in Idaho, with no IC 63-3022H deduction available. Selling a recently purchased Idaho house before hitting the one-year mark costs more on both returns.

Investment and Rental Property: A Different Calculation

If you are selling a rental or investment property in Idaho, the IRC 121 exclusion does not apply unless you converted it to your primary residence and met the two-of-five-year use rule. The full capital gain is taxable.

For a Nampa duplex bought in 2018 for $240,000 and sold in 2026 for $420,000, the gross gain before depreciation recapture is $180,000. Held more than 12 months, IC 63-3022H applies:

• $180,000 gain, minus 60% deduction ($108,000), leaves $72,000 Idaho taxable
• Idaho income tax at 5.3%: $3,816

Depreciation recapture is a separate matter. The portion of gain attributable to prior depreciation deductions is taxed at a maximum federal rate of 25% and is not long-term capital gain for that portion. Idaho income tax at 5.3% also applies to the recapture amount, and the IC 63-3022H deduction does not cover section 1245 recapture.

If you own a rental in Nampa, Meridian, or elsewhere in Ada or Canyon County and are weighing a 1031 exchange against a direct sale, IC 63-3022H reduces the direct-sale tax cost, but a 1031 defers it entirely. Run both numbers before committing to either path.

Idaho Community Property and the Step-Up Basis

Idaho is one of nine community property states. Under IRC 1014(b)(6), community property in Idaho receives a full step-up in basis on both halves at the first spouse’s death, not just the decedent’s share. This is the most favorable basis outcome available under federal law and it can eliminate capital gains entirely on property with years of appreciation.

A house bought jointly for $180,000 in 2004 and worth $450,000 when the first spouse dies in 2024 gets a new basis of $450,000 for both halves. If the surviving spouse then sells for $470,000, the taxable gain is $20,000, not $290,000.

The mechanics of the step-up, the IC 15-6-401 title transfer rules, and the IRC 121(b)(2)(B) two-year window for surviving spouses are covered in depth at Selling a House After Your Spouse Dies in Idaho.

Who Should Not Sell to a Cash Buyer for Tax Reasons

A cash sale does not change your tax liability. You owe the same Idaho income tax on the same gain regardless of who buys the house or how they pay. These situations are usually better served by a different approach:

• High-equity investment properties where a 1031 exchange is viable. A 1031 exchange defers all Idaho income tax on the gain indefinitely. A direct cash sale closes out the deferral and triggers the tax in the year of sale.
• Primary residence sellers whose full gain falls below the IRC 121 threshold. If the $250,000 or $500,000 exclusion covers your entire gain, you owe nothing at either the federal or Idaho level. A conventional sale through a realtor may net a higher price, and the tax outcome is the same.
• Sellers who have not yet met the two-of-five-year use requirement but could with more time. If you are at 18 months and could qualify in six more, the difference between zero Idaho tax and a 5.3% bill on the taxable gain can be significant. Compare carrying costs against the tax savings before deciding.
• Sellers with large gains who have not confirmed IC 63-3022H applies to their property type. The 60% deduction does not apply to every property. Get the Form CG analysis from an Idaho CPA before closing on any sale where the deduction is material to your decision.

Cash sales make the most sense when title complexity, condition, timeline, or out-of-state logistics matter more than maximizing net proceeds. The tax calculation is identical to a conventional sale either way. For decisions that depend on the specific numbers, consult an Idaho CPA or tax attorney.

Common Questions

Does Idaho charge capital gains tax on home sales?

Idaho does not have a separate capital gains tax. Gains from selling real property are taxed as ordinary income at the 5.3% flat rate. Most primary residence sellers owe nothing because the federal IRC 121 exclusion covers the full gain. For gains above the exclusion threshold, Idaho taxes the remainder after applying the 60% deduction under IC 63-3022H for qualifying real property held 12 months or longer.

What is Idaho’s capital gains tax rate in 2026?

Idaho’s flat income tax rate for 2025 and forward is 5.3%, enacted by House Bill 40 in March 2025. Capital gains are included in ordinary income and taxed at the same rate. For qualifying real property held at least 12 months, the IC 63-3022H deduction reduces the taxable amount by 60%, leaving an effective Idaho rate of 2.12% on that portion.

Do I have to pay capital gains if I sell my Idaho house and buy another one?

Buying a replacement home does not defer or eliminate capital gains taxes on the sale. The IRC 1034 rollover that once allowed this was repealed in 1997. Today, the IRC 121 primary residence exclusion covers up to $250,000 for single filers or $500,000 for married couples on a qualifying primary residence sale. The purchase of a new home has no effect on the tax owed on the sale. A 1031 exchange deferral is available for investment properties only, not primary residences.

How do I figure out whether my gain is above the exclusion threshold?

Start with your sale price. Subtract your adjusted basis: original purchase price plus capital improvements and qualifying closing costs paid at purchase. If the result falls below $250,000 for a single filer or $500,000 for a married couple, and you have met the two-of-five-year use requirement, you likely owe nothing at the federal or Idaho level. If you are above those thresholds, run the numbers with an Idaho CPA before closing.

If you want a cash offer on your Idaho property, request one here. We buy in all Idaho markets, close in as few as 7 days or on your schedule, and there are no commissions or fees. Call (208) 540-8257 for a same-day offer.