Selling Your Home in Retirement? How the Gain Can Raise Your Medicare Premiums and Taxes

Retirees selling a long-held Orange County home usually ask 1 question: how much capital gains tax will I owe? That is only the first domino. A large gain also counts as income, and income is what drives your Medicare premiums, how much of your Social Security gets taxed, whether you can claim newer senior deductions, and how much you need to send the IRS and the Franchise Tax Board during the year.

As a CPA and a Realtor, this is the part of a sale I see catch people off guard most often. Here are the ripple effects, 1 at a time.

This article is general education, not tax or legal advice. Confirm your own numbers with your CPA or tax adviser before you list or sign anything.

First, a Quick Word on the Gain Itself

Federal law lets you exclude up to $250,000 of gain ($500,000 for married couples filing jointly) on a principal residence you have owned and lived in for 2 of the last 5 years; anything above that is taxable, and the excess can also be hit by the 3.8% Net Investment Income Tax. We cover those rules in detail in our guide to capital gains tax on a home sale in California, and how to document your basis (and when an installment sale makes sense) in our post on cost basis for a high-value Newport Beach sale.

What matters here: the taxable portion of your gain is added to your adjusted gross income (AGI) for the year. For a couple who bought in Newport Beach or Irvine decades ago, that can be several hundred thousand dollars.

Ripple 1: Medicare IRMAA Surcharges, 2 Years Later

If you are on Medicare, your Part B and Part D premiums are based on your income. Higher earners pay an Income-Related Monthly Adjustment Amount, known as IRMAA. According to CMS's 2026 premium fact sheet, the standard Part B premium for 2026 is $202.90 a month, and only about 8% of Part B enrollees pay the surcharge. A big home sale can put you in that 8% for a year.

How the 2-year lookback works

Social Security uses your tax return from 2 years earlier. Per the Social Security Administration's premium page, 2026 premiums are generally based on the 2024 tax return. So if you sell in 2026, the gain shows up on your 2026 return, and the surcharge shows up on your Medicare bill in 2028. Many people assume that bill is a mistake.

SSA measures income using modified adjusted gross income (MAGI), which is your AGI plus tax-exempt interest. Municipal bond interest does not keep you out of IRMAA.

The 2026 IRMAA brackets

Here are the 2026 brackets, as published by SSA and CMS. These are the monthly amounts added per person on top of the $202.90 standard Part B premium and your Part D plan premium. Brackets adjust yearly, so those for a 2026 sale (billed in 2028) will be set later.

What that costs in real dollars

Take a married couple, both on Medicare, whose sale-year MAGI lands at $800,000 because of a taxable gain. Using 2026 figures, each spouse would pay an extra $487.00 for Part B and $91.00 for Part D, or $578 a month. That is $6,936 per person and $13,872 for the couple, for 1 year of premiums.

2 points worth knowing:

• The brackets are cliffs. Going $1 over a threshold triggers that tier's full surcharge.
• It is usually a 1-year event. If income drops back after the sale year, premiums follow 2 years later.

Can you appeal it?

SSA lets you request a new decision using Form SSA-44 if you had a qualifying life-changing event, such as the death of a spouse, divorce, retirement or reduced work, or loss of income-producing property. A voluntary home sale is not on SSA's list. If the sale coincided with retirement or the loss of a spouse, though, that event may support a request, so raise it with your adviser. If you amend a tax return that changes your MAGI, SSA says you can send it in and they will correct the surcharge.

Ripple 2: More of Your Social Security Becomes Taxable

Federal tax on Social Security benefits depends on what the IRS calls "combined income": half of your benefits plus all your other income, including tax-exempt interest. According to IRS Publication 915, benefits start becoming taxable above a base amount of $25,000 for single filers and $32,000 for married couples filing jointly, and up to 85% of benefits can be taxable at higher incomes. Those base amounts are not indexed for inflation.

Retirees with sizable pensions or IRA withdrawals are often already at the 85% level. But if you have been living mostly on Social Security and savings, a taxable gain will likely push you to the 85% maximum for that year, and those extra taxable benefits are taxed at ordinary rates.

The good news at the state level: California does not tax Social Security benefits at all, so this ripple is federal only.

Ripple 3: Losing the New Senior Deduction

The 2025 federal tax law added an extra deduction of up to $6,000 per person for taxpayers 65 and older, or up to $12,000 for a married couple where both qualify. The IRS explains in its fact sheet on the new deductions that it applies for tax years 2025 through 2028 and starts phasing out once MAGI goes above $75,000 for single filers and $150,000 for joint filers.

A large taxable gain can wipe out this deduction for the sale year, and it is easy to miss.

Ripple 4: Estimated Taxes and the Underpayment Penalty

When you sell a house, no one withholds income tax for you (unless you are a foreign seller, which is a separate topic covered in our post on FIRPTA and withholding when selling in Newport Beach). If you wait until April to pay the tax on a large gain, you may owe an underpayment penalty on top of the tax.

The federal safe harbor

Per IRS Publication 505, you generally avoid the federal penalty if your withholding and estimated payments cover the smaller of 90% of this year's tax or 100% of last year's tax. If last year's AGI was above $150,000 ($75,000 if married filing separately), that prior-year figure rises to 110%. The 2026 federal due dates are April 15, June 15 and September 15 of 2026, and January 15, 2027.

For many retirees, the prior-year safe harbor is the cleanest path: pay in 100% (or 110%) of last year's tax during the sale year, and the balance on the gain can wait until April. If you close late in the year, the annualized income installment method can match payments to when the income arrived.

California is stricter

California has its own rules, and 2 of them trip people up. First, the Franchise Tax Board's estimated tax page shows that California front-loads its payments: 30% due April 15, 40% due June 15, nothing in September, and 30% due January 15. Second, if your California AGI for the year is $1,000,000 or more, the prior-year safe harbor is not available. You must pay based on 90% of the current year's tax. A large Newport Coast or Corona del Mar sale can push a retired couple over that line for the year, and then the "just pay last year's amount" approach no longer protects you at the state level.

And because California taxes all capital gains as ordinary income, with no lower rate for long-term gains, the state share of the bill on a large gain is often bigger than sellers expect.

Ripple 5: Coordinating IRA Withdrawals and Roth Conversions

The sale year is not the year to stack extra income on top of the gain if you can avoid it. Traditional IRA withdrawals and Roth conversions both add to AGI, which means they push you further into IRMAA tiers, fill up higher brackets, and can push more of your gain into the Net Investment Income Tax.

Some practical ideas to discuss with your CPA:

• Skip or shrink a planned Roth conversion in the sale year. Consider doing more in the years before or after, when your income is lower.
• Pull extra IRA money the year before the sale, not the year of it, if you know a large gain is coming and you need cash for the move.
• Use cash or proceeds to cover living costs in the sale year, instead of taxable IRA withdrawals beyond any required minimum distribution, which you still must take.
• Consider the timing of the closing itself. Closing in early January instead of late December moves the entire gain, and the IRMAA hit, into a different year. Our post on the best time to sell your Newport Beach home covers the market side of that decision.
• Harvest investment losses in the sale year to offset taxable gain above the exclusion.

The flip side: the year after the sale, when income drops back, can be a good window for a Roth conversion.

Property tax is a separate question from income tax. If you are buying a smaller home, Prop 19 may let you carry your current assessed value with you; see our guide to who qualifies for Prop 19 and how the transfer works.

A Simple Sale-Year Checklist

1. Estimate your taxable gain before you list, using real basis records.
2. Have your CPA run a sale-year projection that includes Medicare, Social Security and the senior deduction, not just the capital gains tax.
3. Decide on closing timing with the tax calendar in mind, not only the market calendar.
4. Pause or reshape Roth conversions and extra IRA withdrawals for the sale year.
5. Set up federal and California estimated payments so you meet a safe harbor.
6. Put a note in your files that your Medicare premium will likely rise 2 years later, and budget for it.

If you are still early in the process, our 2026 guide to downsizing in Newport Beach and our breakdown of what it costs to sell a house in Orange County fill in the rest of the picture.

Frequently Asked Questions

Will selling my home raise my Medicare premiums?

It can, if the taxable part of your gain pushes your MAGI above the IRMAA thresholds, which for 2026 start at $109,000 for single filers and $218,000 for joint filers. The increase shows up 2 years after the sale year, because Social Security uses your tax return from 2 years earlier.

Does the excluded part of my gain count toward IRMAA?

No. Gain you exclude under the $250,000 or $500,000 home-sale exclusion is not included in AGI, so it does not count toward MAGI for IRMAA. Only the taxable portion above the exclusion counts.

Can I appeal an IRMAA surcharge caused by a home sale?

A voluntary home sale is not one of SSA's listed life-changing events for Form SSA-44. If the sale happened alongside a qualifying event, such as retirement, divorce or the death of a spouse, that event may support a request for a new decision. Ask your adviser before filing.

Will my Social Security benefits be taxed more in the year I sell?

Possibly. Up to 85% of benefits can be federally taxable once your combined income passes the base amounts. If you are not already at the 85% level, a taxable gain will likely put you there for that year. California does not tax Social Security.

Do I need to make estimated tax payments after selling my house?

Often, yes. No tax is withheld on a typical home sale. You can usually avoid the federal penalty by paying at least 100% of last year's tax (110% if last year's AGI was over $150,000). In California, if your AGI for the year reaches $1,000,000, you must pay based on 90% of the current year's tax instead.

Should I do a Roth conversion in the same year I sell my home?

Usually it is better not to stack them. A conversion adds to AGI on top of the gain, which can raise your IRMAA tier and your tax bracket. Many retirees shift conversions to the year before or after the sale.

Plan the Whole Year, Not Just the Sale

The capital gains bill is the number everyone watches. The Medicare surcharge, Social Security tax and estimated payment rules are the ones that surprise people. Planned early, most can be reduced or budgeted for.

Vida and I help Orange County homeowners time and structure their sales with the full financial picture in mind, and we work alongside your CPA and financial planner. Book a complimentary consultation or call us at 714-612-3870.

Dar Mardan, CPA, MBA | Vidar Group Real Estate – REAL Broker