Most California homeowners who sell their primary residence pay zero federal income tax on the gain. The federal rule lives at Internal Revenue Code section 121: up to $250,000 of gain excluded for a single filer, $500,000 for a married couple filing jointly. California conforms. But the rule has specific tests, common traps, and a depreciation recapture hook that catches anyone who ever converted the home to a rental. I'm Brian Cooper, REALTOR(R) at eXp Realty (DRE# 01434286), and this is the 2026 playbook for Ventura County sellers.
Quick Answer
IRC section 121 lets you exclude up to $250,000 of capital gain from federal income tax on the sale of your principal residence ($500,000 if married filing jointly). To qualify, you must have owned the home for at least 2 of the 5 years before the sale AND used the home as your principal residence for at least 2 of the 5 years before the sale. The two years of ownership and the two years of use do not have to be the same two years, and the two years do not have to be continuous. California conforms to IRC 121 for state income tax purposes, so the same exclusion applies on your California return.
Gain above the exclusion is taxed as long-term capital gain at federal rates (0%, 15%, or 20% depending on income) plus the 3.8% Net Investment Income Tax if applicable, plus California ordinary income tax (up to 13.3% for the highest earners; California does not have a preferential capital gains rate). The exclusion can be used repeatedly throughout your lifetime, but only once every two years. A common Simi Valley couple selling a home they bought in 2014 for $450,000 and selling in 2026 for $1,050,000 with no rental period pays zero federal capital gains tax on the $600,000 gain, because the $500K MFJ exclusion plus a stepped basis from improvements wipes out the taxable gain.
IRC 121 mechanics: ownership AND use
The statute requires two separate tests, both of which have to be met. The ownership test: you owned the home for at least 24 months out of the 60 months before sale. The use test: you used the home as your principal residence for at least 24 months out of the 60 months before sale. The 24 months of ownership and the 24 months of use can overlap or not, can be continuous or broken into shorter periods, and do not have to align with each other.
Example: you bought the home in January 2020, lived there as your primary residence until December 2022, moved out and rented to a tenant from January 2023 through December 2024, then sold in February 2026. Ownership: 73 months, easily over 24. Use as principal residence: 36 months (Jan 2020 through Dec 2022), comfortably over 24. Exclusion applies, subject to depreciation recapture on the rental period.
Married couples filing jointly need both spouses to meet the use test, and at least one spouse to meet the ownership test. If only one spouse meets the use test, the couple is limited to the $250,000 single-filer exclusion, not the $500,000 joint exclusion.
Partial exclusion: job, health, unforeseen circumstances
If you fail the 2-of-5 test because of a qualifying reason, IRC 121(c) allows a partial exclusion. The three statutory categories are: change in place of employment, health, and unforeseen circumstances. Treasury Regulation 1.121-3 defines each. The partial exclusion is calculated by multiplying the full exclusion ($250K or $500K) by a fraction: months of use divided by 24.
Job change: you have to move at least 50 miles farther from the old home than the previous commute. A move from Simi Valley to a new job in downtown LA does not automatically qualify; the new job has to be 50 miles farther from the old home than the old job was. Health: documented medical reason for the move, including obtaining or providing medical care for the taxpayer, spouse, or close family member. Unforeseen circumstances: specifically defined safe harbors include death, divorce, multiple births from the same pregnancy, unemployment qualifying for unemployment compensation, and natural disasters.
Worked example: married couple buys a home in May 2025, then one spouse takes a job in Texas in February 2026 meeting the 50-mile test. They sell the home after 9 months of use. Partial exclusion: 9/24 × $500,000 = $187,500. Gain above $187,500 is taxable. Document the qualifying reason at the time of sale; the IRS asks on audit.
Depreciation recapture from rental conversions
If you ever converted the home to a rental and took depreciation, IRC 1250 recaptures the depreciation at a 25% federal rate (the 'unrecaptured Section 1250 gain' rate), even if the underlying gain would otherwise be excluded under IRC 121. Recapture is limited to depreciation actually taken (or allowable, whichever is greater). You cannot exclude recapture under the $250K/$500K limits.
Example: bought in 2014 for $450K. Rented from 2016 to 2020, took $40K of depreciation. Moved back in 2020. Sold in 2026 for $1,050,000. Gain is $600K. Of that gain, $40K is unrecaptured Section 1250 gain taxed at 25% federal ($10K federal tax). The remaining $560K is potentially excludable under IRC 121 — wholly inside the $500K MFJ exclusion plus the basis additions for improvements, so the rest may be tax-free.
California treats the depreciation recapture as ordinary income at California marginal rates. There is no California preferential capital gains rate. Calculate state tax exposure separately.
California conformity (with a few exceptions)
California generally conforms to IRC 121 under Rev & Tax Code 17152. The $250K single / $500K MFJ exclusion applies to California state income tax. Partial exclusions for job change, health, and unforeseen circumstances also apply to California tax.
Two California-specific things to watch. First, California does not have a separate long-term capital gains rate. Gain above the IRC 121 exclusion is taxed at California ordinary income rates, which can hit 13.3% for the highest earners. A Simi Valley seller with $200,000 of gain above the IRC 121 exclusion who falls in the 9.3% California bracket owes about $18,600 in California tax even though federal capital gains tax may be 0% at that income level.
Second, California Franchise Tax Board has its own form (Schedule D-540) for reporting the gain. The IRC 121 exclusion is reported through Form 8949 and Schedule D federally, and the California return mirrors the federal treatment via Schedule D-540. California withholding under FTB 3848 (formerly 593) is collected at closing by the escrow officer unless the seller files for an exemption. Most primary-residence sales qualify for the exemption via the seller's affidavit at closing.
What 'basis' includes: improvements vs repairs
Basis is the figure you subtract from sale price to calculate gain. Starting basis is what you paid for the home plus purchase costs (title insurance, escrow fees, recording fees, transfer taxes you paid). Basis goes up by the cost of capital improvements during ownership. Basis goes down by depreciation you took during any rental period and by casualty losses you deducted.
Capital improvements add to basis: a new roof, a kitchen remodel, an added bathroom, a swimming pool, solar panels, room additions, HVAC system replacement, driveway replacement, permanent landscaping, electrical and plumbing upgrades. Keep receipts and contractor invoices for at least 3 years after the sale (longer if you might face an audit).
Repairs do not add to basis: painting, fixing a leaky faucet, replacing a broken window, patching a roof leak, cleaning carpet, replacing a thermostat. The IRS distinguishes by the purpose: fixing something to its original condition is a repair (no basis addition), upgrading or extending the useful life is an improvement (adds to basis). Painting as part of a major remodel can be improvement; standalone painting is repair.
I tell sellers to pull together all improvement receipts before closing. On a 10+ year hold in Simi Valley, basis additions of $50K-$100K are common (new HVAC, roof, kitchen, bathrooms, solar) and they can move the taxable gain calculation materially.
Selling at a loss: no deduction
Loss on the sale of a personal-use primary residence is not deductible. IRC 165(c) limits deductible losses to trade/business losses, investment losses, and casualty losses. A personal-use residence is none of those. If you sell your Simi Valley primary residence for less than basis, the loss is non-deductible.
If the home had been converted to a rental at some point, a portion of the loss attributable to the rental period may be deductible as a rental property loss, but only if the conversion was bona fide and the basis for depreciation was properly set at conversion. Talk to a CPA about basis bifurcation before assuming a loss is deductible.
California follows federal treatment. No California deduction for primary-residence loss either.
Section 121 vs 1031: when to use which
IRC 121 is for primary residences. IRC 1031 is for investment / business property. They are not interchangeable, but in narrow circumstances they can stack.
Use 121 when: the home was your primary residence for at least 2 of the last 5 years, the gain is at or below the $250K / $500K limit, and you intend to deploy the proceeds without restrictions (buy a new primary residence, retire, invest in stocks, anything). 121 is simpler, no replacement-property rules, no 45-day identification window, no 180-day closing window.
Use 1031 when: the property is held for investment or business use (rental property, not your home), the gain is large enough to make the deferral worth the cost and complexity, and you intend to buy replacement investment property of equal or greater value within the 180-day window.
Mixed-use stack: if a home was your primary residence for part of the holding period and a rental for part of the holding period, you can in some cases use IRC 121 on the residence portion AND IRC 1031 on the rental portion of the basis. The calculation is technical, and Rev. Proc. 2005-14 outlines the safe harbor for combining the two. Work with a 1031 qualified intermediary and a CPA.
Worked example: Simi Valley home, 2014-2026
Married couple bought a 4-bedroom Simi Valley home in March 2014 for $450,000. Lived in it continuously as their primary residence. Sold in May 2026 for $1,050,000. No rental period, no depreciation, filed jointly. Closing costs at sale: $63,000 (commissions, title, escrow, transfer tax). Capital improvements documented over the hold: $72,000 (new roof in 2018 $18K, kitchen remodel 2020 $35K, solar in 2022 $19K — all with receipts).
- Sale price: $1,050,000
- Less selling costs: $63,000
- Amount realized: $987,000
- Adjusted basis: $450,000 + $72,000 improvements = $522,000
- Realized gain: $987,000 - $522,000 = $465,000
- IRC 121 MFJ exclusion: $500,000
- Taxable gain: $0 (gain is under the exclusion)
- Federal capital gains tax: $0
- California state tax on the gain: $0
If the same couple sold for $1,150,000 with the same improvements and selling costs, realized gain would be $565,000, exceeding the $500K exclusion by $65,000. That $65,000 would be taxed: at federal long-term capital gains rates (0%, 15%, or 20% depending on AGI; for most middle-income couples, 15% = $9,750), plus California ordinary income tax on the same $65,000 (at, say, the 9.3% bracket = $6,045). Total tax exposure on the over-cap portion: ~$15,800.
Frequently Asked Questions
Can I use the exclusion more than once?
Yes. The exclusion can be used repeatedly throughout your lifetime, but no more often than once every two years. The two-year clock runs from one qualifying sale to the next. Sales within two years of a prior IRC 121 sale are ineligible for the exclusion.
Does the exclusion apply to vacation homes or rentals?
No. IRC 121 covers only the principal residence — the home you actually live in most of the year. Vacation homes, second homes, and rental property are not eligible. A property that was your principal residence for at least 2 of the last 5 years qualifies even if it became a vacation home or rental in the most recent year or two.
What happens if I'm a widow or widower?
If you sell within 2 years of your spouse's death and meet the joint-return requirements at the time of death, the surviving spouse may claim the $500K MFJ exclusion under IRC 121(b)(4). Beyond 2 years, the survivor is limited to the $250K single-filer exclusion.
Does California require me to report the sale even if no tax is due?
Yes. Report the sale on Schedule D-540 with the IRC 121 exclusion shown. Escrow will file FTB Form 593 (now FTB 3848) at closing. The seller's affidavit at closing typically exempts a primary-residence sale from California withholding, but the sale must still be reported on the tax return.
What if I make improvements during the marriage but only one spouse paid for them?
Improvements that increase basis are tracked by ownership, not who wrote the check. If the home is community property, improvements increase the community basis regardless of which spouse funded them. If the home is separate property of one spouse, improvements funded by the other spouse can create reimbursement claims under Family Code 2640 but typically don't change income tax basis treatment.
Does the exclusion cover gain from a home office deduction?
Office space depreciation taken under a home office deduction is subject to depreciation recapture at 25% federal even if the rest of the gain is excluded. The square-footage portion previously claimed as office may also be excluded from the IRC 121 exclusion proportionally if it was non-residential use.
Can I claim the exclusion if my home was destroyed in a fire?
Possibly. Involuntary conversion under IRC 1033 has its own rules, but the IRC 121 exclusion can apply to the gain portion as well. Coordinate with a CPA familiar with both sections. Common after Woolsey or wildfire reconstruction in Ventura County.
Does the IRC 121 exclusion change with inflation?
No. Unlike Prop 19's inflation-adjusted cap, the $250K / $500K IRC 121 exclusion is statutory and fixed. It has not been increased since enactment in 1997. Inflation has materially eroded its value in California; in 1997 the median Ventura County home was under $200K, so $500K covered virtually all gains. In 2026 with a median over $850K, many sellers exceed the cap.
