Home Sale Capital Gains Tax Calculator
Selling your home? The Section 121 exclusion shields up to $500,000 of gain from tax. This calculator applies the exclusion and computes any remaining tax liability.
About this tool
A primary residence sale with 2-of-5-year occupancy qualifies for the Section 121 exclusion — $250,000 for single filers, $500,000 for married filing jointly. Only the gain above the exclusion is taxable. This calculator applies the exclusion correctly.
How to use it
Quick steps to get the most out of this utility.
- 1
Enter home purchase and sale details
Purchase price, improvements, sale price, selling costs.
- 2
Confirm primary residence eligibility
Lived in home 2 of last 5 years enables the exclusion.
- 3
Enter filing status and income
Determines exclusion amount and LTCG bracket.
- 4
See taxable gain and tax
Gain after exclusion, long-term capital gains tax, NIIT, and state.
Section 121: The Most Valuable Tax Break in the Code
The Section 121 exclusion is one of the most generous tax benefits for ordinary Americans. A married couple who bought a home for $400,000 and sold for $1,000,000 with $100,000 in improvements has a $500,000 gain. With the $500,000 MFJ exclusion, the entire gain is tax-free — saving potentially $75,000+ in federal capital gains tax and NIIT. The exclusion can be used once every two years, and the 2-of-5-year rule allows flexibility for homeowners who move frequently.
Frequently asked questions
Does Section 121 apply if I haven't lived there for 2 years?+
Partial exclusions are available if you have to move for specific reasons (job change, health, unforeseen circumstances) before meeting the 2-year threshold. The exclusion is prorated: if you lived there 18 of the required 24 months (75%), you get 75% of the full exclusion. A qualified tax advisor can help determine if your situation qualifies.
Do improvements to my home reduce capital gains?+
Yes — improvements add to your cost basis, reducing the gain. Capital improvements (new roof, addition, kitchen remodel) increase basis. Repairs and maintenance do not. Keep all improvement receipts permanently — they reduce your tax bill when you sell. This calculator includes an improvements field for this purpose.
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