Here’s the reassuring part first: one of the most generous breaks in the entire tax code is the one that applies when you sell your home, and for the majority of sellers it still shields the full gain. The capital gains exclusion on a primary residence hasn’t changed since the Clinton administration, which in a region like ours simply means it pays to know where you stand. For the longtime owners we work with across Marin and San Francisco, a little planning ahead turns this rule from an afterthought into an advantage.
Key Takeaways
Section 121 lets you exclude up to $250,000 of home sale gain if single, or $500,000 if married filing jointly, provided you’ve owned and lived in the home two of the last five years.
For most sellers, that exclusion still covers the entire gain, so there’s nothing owed at all.
The caps were set in 1997 and never indexed to inflation; adjusted for inflation they’d be roughly double today, about $500,000 and $1 million.
In Marin and San Francisco, where a longtime home can carry a gain well into seven figures, some sellers do cross the cap, which is exactly why a little planning pays off.
Your cost basis, capital improvements, and selling costs all reduce the taxable number, so run your gain before you list and keep more of it.
According to the National Association of Realtors, nearly 29 million homeowners, roughly one in three, now hold gains above the $250,000 single filer threshold, and about 10% have enough gain to top the $500,000 married filing jointly amount. The encouraging news is that for owners who understand the math early, this is a problem you can plan around rather than discover at the closing table.
What Section 121 Actually Says
Under Section 121 of the tax code, a homeowner can exclude up to $250,000 of gain from a home sale if filing single, or $500,000 if married filing jointly. The eligibility test is refreshingly simple: you need to have owned and lived in the home for at least two of the previous five years. For a great many sellers, that’s the whole story, and nothing is owed. Only the gain above those thresholds is generally taxable.
The one wrinkle is that those figures were set in 1997 and were never indexed to inflation. That was a comfortable cap in 1997, and for most of the country it still is. In high value pockets like ours, it’s simply worth a second look.
Numbers From 1997, Prices From 2026
Because the thresholds were frozen, they haven’t kept pace with the market around them. Had the caps simply tracked inflation, they’d be roughly double what they are now, somewhere around $500,000 for individuals and $1 million for couples, based on standard inflation data showing the dollar has lost about half its value since 1997.
When the exclusion was written, very few sales produced more than half a million dollars in gain, so the cap rarely came into play. In most of the country that’s still true. The place you’re most likely to see the difference is a region where a home bought decades ago has appreciated into seven figure territory on its own.
Why It Matters More in Marin and San Francisco
This is where a national rule gets a local accent, and it’s good news for most owners. Picture a couple who bought a Mill Valley home in the mid 1980s, when homes across Marin commonly traded in the low to mid six figures. Federal Housing Finance Agency data shows Marin home values have since climbed several times over, and today Mill Valley’s median sale price sits near $2.3 million. On a home bought decades ago for a few hundred thousand dollars, that’s a gain comfortably past a million, so the $500,000 couples’ exclusion covers a large slice of it, with planning available for the rest. A share of sellers here do reach and pass the married filing jointly cap, something that was almost unheard of when the law was written, and knowing that in advance is half the battle.
NAR has noted that the older thresholds can contribute to a lock in effect, where some longtime owners postpone selling to sidestep a tax bill, which keeps inventory tight. The flip side is just as real: owners who plan the timing and the numbers early tend to move with confidence, and they’re the ones who come out ahead in a supply constrained market.
What’s Being Proposed, and What Isn’t Settled
There’s also momentum on the horizon. Several reform efforts are in motion at the federal level, though none has become law yet. A bill known as the No Tax on Home Sales Act, introduced in 2025, would eliminate the capital gains tax on primary residences entirely. A separate bipartisan proposal, the More Homes on the Market Act, would double the exclusion to $500,000 and $1 million and index it to inflation going forward. Beyond the bills, administration officials have floated related ideas, including indexing gains to inflation and exempting homes under a certain value.
For now, these remain proposals. The sensible approach is to plan around current law and treat any future reform as a welcome bonus rather than a reason to wait.
If You’re Weighing a Move
The best news is how much of the outcome is within your control. If you’ve owned your home for many years, the single most useful step is to estimate your potential taxable gain before you list, not after. Several levers work in your favor: documented capital improvements raise your cost basis, selling costs reduce the taxable gain, and confirming you meet the residency test, living in the home two of the last five years, locks in your eligibility from the start.
Every situation is different, so this is a great conversation to have with a qualified CPA or tax advisor. We’re not tax professionals, but we work alongside them regularly and help clients think through timing and positioning so the numbers are clear long before closing. The natural starting point is an accurate read on what your home is worth today, which is exactly what our Home Valuation is built to give you.
Looking Ahead: Making the Rule Work for You
The exclusion still shields the full gain for most sellers in this country, and that’s worth celebrating. In a market like ours, the owners it doesn’t fully cover tend to be the ones with the most equity, which is a good problem to have and a very manageable one with the right plan.
The owners who move well here aren’t the ones who got lucky. They’re the ones who ran the numbers early and built their move around the rules as they actually are. If you’ve been curious about what a sale might look like for you, let’s walk through it together. We’ll help you understand exactly where you stand well before your home ever hits the market.
Frequently Asked Questions
How much home sale gain can I exclude from capital gains tax?
Up to $250,000 if you file single, or $500,000 if you’re married filing jointly, as long as you meet the ownership and residency requirements. For most sellers that covers the entire gain. Only amounts above the cap are generally taxable.
Do the $250,000 and $500,000 limits adjust for inflation?
No. They were set in 1997 and have never been indexed. Adjusted for inflation, they’d be roughly double today, which is why some high value Bay Area sales now reach the cap.
How do I qualify for the exclusion?
You generally must have owned and lived in the home as your primary residence for at least two of the five years before the sale. Meeting this test locks in your eligibility.
What happens if my gain is larger than the exclusion?
Only the portion above your $250,000 or $500,000 cap is typically subject to capital gains tax, and a few planning levers can reduce even that. This comes up for longtime Bay Area owners, which is why estimating the number early helps.
Can improvements or selling costs lower my taxable gain?
Yes. Documented capital improvements raise your cost basis, and selling costs reduce the taxable gain. Both can meaningfully shrink what’s taxable, so keep good records.
Have the proposed tax changes passed?
Not yet. As of late 2026, bills like the No Tax on Home Sales Act and the More Homes on the Market Act remain proposals in committee, so any decision today should be based on current law.
Disclaimer: This article is for general information and isn’t tax advice. Please consult a qualified CPA or tax advisor about your specific situation.
Sources: National Association of Realtors (narfocus.com); Federal Housing Finance Agency (fhfa.gov); CBS News (cbsnews.com); RISMedia (rismedia.com)
