The Basic Formula: Income and Enrollment Timing
Medicare Part B premiums are not flat. Your monthly cost depends on two things: how much you earned two years ago, and whether you signed up when you first became may be able to access. The Social Security Administration looks at your Modified Adjusted Gross Income (MAGI) from two years prior — so in 2024, they use your 2022 tax return — and places you into one of five income brackets. Each bracket has its own premium amount.
If you enrolled in Part B when you first turned 65 or became may be able to access, you pay the standard premium for your income bracket. If you delayed enrollment and signed up later, you pay a late enrollment penalty on top of the standard premium. That penalty is 10 percent of the standard premium for each full year you delayed, and it stays on your bill for as long as you have Part B.
The standard premium itself changes every year. In 2024, the base premium was $164.90 per month, but your actual premium may be higher or lower depending on your income bracket. The income thresholds and premium amounts are set by Medicare and announced each October for the following year.
Key Takeaways
- Your Part B premium is based on your Modified Adjusted Gross Income from two years ago, placed into one of five income brackets with different monthly costs.
- If you enrolled late — after your initial may be able to access period — you pay a permanent 10 percent penalty per year of delay on top of your standard premium.
- The income thresholds and premium amounts change yearly and are announced in October for the following year.
- Married couples filing jointly have higher income thresholds than single filers, so your filing status matters to which bracket you fall into.
- If your income drops significantly due to retirement or life changes, you can request a recalculation based on your current year income instead of the two-year-old figure.
The Five Income Brackets and 2024 Premium Amounts
Medicare divides Part B enrollees into five tiers. The lowest tier pays the standard premium. Each higher tier pays more, with the increase based on income level. For 2024, the brackets and monthly premiums were:
| Income Level (Single / Married Filing Jointly) | Monthly Premium |
|---|---|
| $97,000 or less / $194,000 or less | $164.90 |
| $97,001–$121,500 / $194,001–$243,000 | $230.80 |
| $121,501–$152,500 / $243,001–$305,000 | $329.70 |
| $152,501–$182,500 / $305,001–$365,000 | $428.60 |
| Over $182,500 / Over $365,000 | $527.50 |
These amounts change yearly. The income thresholds also shift each year based on inflation. Because Medicare uses your income from two years ago, you may not know your exact premium until Social Security sends you a notice in the fall.
Late Enrollment Penalties and How They Work
A late enrollment penalty applies if you did not sign up for Part B during your Initial Enrollment Period — the seven-month window that begins three months before the month you turn 65. If you missed that window and did not have creditable coverage (such as employer health insurance), you owe a penalty.
The penalty is 10 percent of the standard premium for each full year you were may be able to access but not enrolled. If you delayed for three years, you pay 30 percent extra on top of your standard premium. Unlike the income-based increases, this penalty does not change year to year — it is calculated once based on how long you waited and stays on your bill permanently.
The only way to remove a late enrollment penalty is to have had creditable coverage during the time you were not enrolled in Part B. Creditable coverage means health insurance as good as or better than Part B — typically employer coverage or retiree coverage. If you can prove you had it, you can request that Social Security remove the penalty retroactively.
How Income Changes Affect Your Premium
Because Medicare uses income from two years ago, a major life change — retirement, a large inheritance, the sale of a home — may not affect your premium when ready. If you retired and your income dropped sharply, you are still paying based on the higher income from two years prior. However, you can request a Life Changing Event recalculation.
To may have access to, you must have experienced a specific event: retirement, loss of income, loss of a spouse, or loss of coverage. You file a form with Social Security (SSA-44) and provide proof — a retirement letter, a death certificate, a notice of job loss. If approved, Medicare recalculates your premium based on your current year income instead of the two-year-old figure. This can lower your premium significantly.
The recalculation is not automatic. You have to request it, and you have a limited window — usually the year the change happened plus the following year. If you retired in 2024, for example, you can request a recalculation in 2024 or 2025, but not in 2026.
What Income Counts Toward Your Premium
Your Modified Adjusted Gross Income includes wages, self-employment income, interest, dividends, capital gains, rental income, and distributions from retirement accounts. It also includes certain tax-exempt interest, such as interest from municipal bonds. It does not include Social Security benefits themselves.
If you are married and file jointly, both spouses' incomes are combined for the threshold calculation. If you file separately, each spouse's income is evaluated individually, but the income thresholds for separate filers are much lower — often making separate filing more expensive. Most couples find joint filing results in a lower premium.
When Your Premium Changes and How You Pay
Your premium is recalculated every January based on the income information Social Security has on file. In October of the previous year, you receive a notice showing your new premium for the coming year. If the amount changes, the notice explains why.
Most people have Part B premiums deducted directly from their Social Security check. If you are not yet receiving Social Security, or if you want to pay another way, you can pay Medicare directly by mail or online through the Medicare website. Payments are due by the 25th of the month for coverage that month.
If you disagree with your premium calculation, you can request a reconsideration. You have 60 days from the date on your notice to ask Social Security to review the income figure they used. Bring your tax return or other proof of income for the year in question.
Frequently Asked Questions
Can I lower my Part B premium if my income dropped after I retired?
Yes, if you experienced a life-changing event like retirement or job loss. You can request a recalculation using your current year income instead of the two-year-old figure. You must file form SSA-44 with Social Security and provide proof of the event. The request must be made in the year the change happened or the year after.
What happens if I don't pay my Part B premium?
If you miss payments, Medicare will send you notices and may eventually disenroll you from Part B. Once you are disenrolled, you cannot re-enroll until the next General Enrollment Period (January through March), and you will owe a late enrollment penalty when you do. It is better to contact Medicare if you are having trouble paying.
Does my spouse's income affect my Part B premium?
Only if you file taxes jointly. If you file jointly, both incomes are combined for the income threshold. If you file separately, each person's income is evaluated alone, but the separate-filer thresholds are much lower, usually resulting in higher premiums for both of you.
Why am I paying more than the standard premium if my income hasn't changed?
Your income from two years ago may have been higher than your current income. Also, if you enrolled late, you are paying a permanent 10 percent penalty per year of delay. The income thresholds and standard premium amounts also increase yearly, which can move you into a higher bracket even if your income stayed the same.
Can I appeal my Part B premium if I think it's wrong?
Yes. You have 60 days from the date on your notice to request a reconsideration. Contact Social Security and provide your tax return or other proof of income for the year they used in the calculation. If Social Security made an error, they will correct it and adjust your premium going forward.