Medicare Part D

2027 Medicare IRMAA Thresholds in Lake Forest, CA

Lake Forest, Calif. — As Medicare's Annual Enrollment Period runs through Dec. 7, many local retirees are opening letters from Social Security and finding a surprise: an extra charge added to their Part B and Part D premiums for 2027. It's called IRMAA — the Income-Related Monthly Adjustment Amount — and it catches thousands of higher-income beneficiaries off guard every year.

Here's a plain-English guide to how income affects your Medicare costs for 2027, where the thresholds sit, and how to avoid the most common mistakes.

What IRMAA actually is

IRMAA is not a separate bill or a penalty. It's an extra amount added to your standard Part B premium and your Part D premium when your income is above a certain level. Social Security calculates it automatically using your tax return from two years ago. So your 2027 IRMAA is based on your 2025 income.

Most people on Medicare pay only the standard Part B premium. IRMAA affects a smaller group — generally the top 8% or so of earners — but if you're in that group, the extra cost can be hundreds of dollars a month.

The 2026 income thresholds

For 2026, the first IRMAA tier begins when your modified adjusted gross income (MAGI) is above:

• $109,000 for individuals filing a single tax return
• $218,000 for married couples filing jointly

Above those numbers, surcharges rise in five brackets, with the highest tier kicking in at $500,000 (single) or $750,000 (joint). Each tier adds a set amount to both your Part B premium and your Part D premium — even if you have a standalone drug plan or drug coverage through Medicare Advantage.

You can see the current bracket chart on Medicare.gov under "Part B costs" and "Part D costs."

How Social Security decides

Two things trip people up here:

1. The two-year lookback. Your 2027 surcharge uses your 2025 tax return. If you had a big one-time event that year — sold a house, cashed out an investment, took a large IRA withdrawal — it can push you into a bracket even if your income has since dropped.

2. MAGI is broader than you think. It includes tax-exempt interest (like muni bond income) on top of your adjusted gross income. That surprises a lot of retirees.

If your income has gone down, you can appeal

This is the most important thing to know. If you've had a "life-changing event" that reduced your income, you can ask Social Security to recalculate your IRMAA using more recent numbers. Qualifying events include:

• Retirement or reduced work hours
• Death of a spouse
• Marriage or divorce
• Loss of pension income
• Loss of income-producing property

You'll file Form SSA-44 with supporting documents. Many Lake Forest residents who recently retired don't realize this option exists — and they pay a full year of surcharges they didn't need to.

Where this fits with the rest of your 2027 costs

IRMAA is one piece of a bigger picture that keeps shifting:

• The Part D out-of-pocket cap on covered drugs is $2,100 in 2026 and $2,400 in 2027. Once you hit it, you pay nothing for the rest of the year on covered prescriptions.
• The Part D deductible maxes out at $615 in 2026 ($700 in 2027).
• The coverage gap ("donut hole") is gone. Part D now has three phases instead of four.
• The Medicare Prescription Payment Plan lets you spread drug costs across the calendar year in monthly installments instead of paying big bills at the pharmacy counter.

IRMAA still gets added on top of whatever Part D plan you choose, so higher earners should factor it into their total drug-coverage math during AEP.

A note on local coverage

Lake Forest is in Orange County, where beneficiaries have a wide selection of Medicare Advantage and standalone Part D plans to compare during AEP. Availability is set at the county level, so two neighbors in the same ZIP code see the same list of options. The number of plans, though, doesn't change your IRMAA — that's driven only by your income and your tax filing status.