How does the step up in basis work when a spouse dies?

Last updated September 1, 2026

By Cade Cashman, Principal Agent, Ascension Estates at Equity Union Real Estate. DRE #02222044.

When a spouse dies, the home's cost basis generally resets to its fair market value on the date of death. In California, a community property state, that reset can apply to the entire home, both the deceased spouse's half and the survivor's half. Gain on a later sale is measured from the new, higher basis, so decades of appreciation can escape income tax entirely.

We are agents, not accountants, and this page walks a hard season. The reason we wrote it anyway is simple. The tax rules that apply after a spouse dies are unusually generous, a few of them have clocks attached, and a surviving spouse who does not know the rules can give six figures back to the IRS by selling at the wrong time or by never getting the right appraisal. Read this, then take it to a CPA.

What is a step up in basis?

Your basis is roughly what you paid for the house plus qualifying improvements. Gain is the sale price minus selling costs minus basis. Lower basis, bigger gain, bigger tax.

Internal Revenue Code section 1014 changes the starting point at death. Property passing from a person who died generally takes a new basis equal to its fair market value on the date of death. The IRS explains the rule in Publication 551, Basis of Assets. The old purchase price stops mattering. The appreciation that built up during the owner's life is never taxed as income to anyone.

Run an illustrative example, clearly labeled as one. A couple bought a home for $200,000 decades ago. It is worth $1,500,000 when one spouse dies. Without any step up, a sale at $1,500,000 would show $1,300,000 of gain before adjustments. With a full step up to date-of-death value, a sale at $1,500,000 shows roughly zero gain, and selling costs can push it to a loss. Same house, same price, completely different tax bill.

What is the double step up for California community property?

This is the part that is specifically Californian, and it is the single most valuable sentence on this page.

In most states, when the first spouse dies, only the deceased spouse's half of a jointly owned home resets to date-of-death value. The survivor's half keeps its old basis, and the appreciation on that half stays taxable.

California is a community property state, and federal law treats community property differently. Under Internal Revenue Code section 1014(b)(6), when one spouse dies, both halves of the community property can receive the new basis. The survivor's own half resets too, even though the survivor did not die. Tax professionals call it the double step up, and it applies in the handful of community property states, California among them.

Continue the illustrative example. On the $200,000 home now worth $1,500,000, a common-law-state survivor might get a basis of $850,000, the stepped-up half plus the old half. A California survivor holding the home as community property can get a basis of the full $1,500,000. That difference is $650,000 of gain that simply never existed for tax purposes.

One thing decides whether you get this. How title was held.

We wrote a full plain-English guide to these choices in community property with right of survivorship. If you are reading this before a death rather than after one, that article is the one that can still change your outcome.

This is not tax advice. Basis at death turns on title, dates, and the character of the property, and the stakes are large. Put a CPA and an estate attorney on your side before you sell. The fee is small against the numbers on this page.

Can a surviving spouse still use the $500,000 exclusion?

Yes, and there is a clock on it.

The Section 121 exclusion lets a married couple filing jointly exclude up to $500,000 of gain on a principal residence, and a single filer up to $250,000. A surviving spouse usually files as single soon after the year of death, which would normally mean the smaller number.

Internal Revenue Code section 121(b)(4) fixes that for a window. A surviving spouse who has not remarried can still use the full $500,000 exclusion if the home sells within 2 years of the date of death, and the couple met the ownership and use tests immediately before the death, and neither spouse had used the exclusion on another home in the prior 2 years. Close escrow at 2 years and a day and the ceiling generally drops to $250,000.

Now put the two rules together, because they interact. With a full double step up, your gain is measured from date-of-death value. Sell reasonably soon and the gain may be small, so the exclusion barely matters. But if the home keeps appreciating after the death, or if title only earned you a half step up, gain builds again, and the difference between a $500,000 ceiling and a $250,000 ceiling gets real. That is why the 2-year mark matters most to survivors who wait.

The full mechanics of the exclusion, including the tests and California's treatment, are in capital gains when you sell a California home. And to be clear about scope, this page is about death, and the rules for a marriage that ends in court are different. Those are covered in selling a house during a divorce in California.

Will my property taxes go up when my spouse dies?

Generally no, and this one is a relief instead of a trap.

Property tax reassessment in California is triggered by a change in ownership. Transfers between spouses, including transfers that take effect on the death of a spouse, are excluded from reassessment under Revenue and Taxation Code section 63. The surviving spouse keeps the existing Prop 13 assessed value, growing at most 2 percent a year, exactly as before. Proposition 19 rewrote the parent-child rules in 2021 and left the interspousal exclusion alone.

So the income tax basis steps up while the property tax base stays put. The two systems run on different rails. The county may still need paperwork recorded to clear the deceased spouse from title, so check with the assessor rather than assuming silence is fine. If children will eventually inherit the home, the rules change again, and the inherited house guide linked below covers what awaits them.

When should I sell after a spouse dies?

The honest answer is that grief sets the real timeline, and the tax code only sets fences around it. Here is where the fences are.

• Get a date-of-death appraisal now, whatever you decide. Your new basis is the fair market value on the date of death, and someday your CPA must prove it. A retrospective appraisal ordered years later is weaker and costlier than one done near the time. This is the single most important practical step on this page.
• There is no tax reason to rush a quick sale. The step up already happened. If you sell within a modest time and prices are stable, gain is small with or without the exclusion.
• The 2-year mark is the first fence. If you might sell but keep deferring, know the date. Closing inside 2 years preserves the $500,000 ceiling. A decision made at 20 months beats a regret at 26.
• Waiting for years is a real strategy too. Some survivors stay for good, and the home passes to heirs with another step up at that point. That is a valid plan. It should just be a chosen plan, with the numbers known, and your heirs' Prop 19 position understood.
• Clear title before you list. Depending on vesting, that can mean recording an affidavit of death, a spousal property petition through the court, or trust administration steps. An attorney or your escrow officer will tell you which applies. It is usually simple, and it is far better handled before a buyer is waiting. Inherited property has its own version of this checklist in selling an inherited house in California.

One honest limitation. We have described stable federal and California law, and the rules here, sections 1014, 121, and Revenue and Taxation Code 63, have held their shape for years. What we cannot see is your title history, your trust, your dates, or your return. Every number above is illustrative arithmetic, and the difference between generally and actually is a professional's job. Our job is the other half: what the house is worth now, what it nets after every cost, and what each of the three exits looks like for you, whether that is listing, a verified cash offer, or waiting with a plan.

This is not tax or legal advice. Basis, the exclusion window, filing status, and title clearing all depend on facts we cannot see, and mistakes here are expensive and sometimes irreversible. Use a CPA and an estate or probate attorney before you sign anything. Bring them this page and your dates.