How to use this calculator
- Choose the premium year: the year you pay the premiums. The calculator tells you which tax return sets it, two years earlier.
- Choose the filing status on that return. If you were married and filed separately, say whether you lived together at any time that year.
- Enter your adjusted gross income from line 11 of that Form 1040 and your tax-exempt interest from line 2a.
- Say who is on Medicare. On a joint return both spouses usually are, and each pays the surcharge. Turn drug coverage off for anyone without a Part D plan or a Medicare Advantage plan with drugs.
- Under More options, add your drug plan's premium and any late-enrollment penalty to see your whole premium.
Planning a Roth conversion, a large withdrawal or a sale this year? That income sets your premiums two years from now, and those brackets are not published yet. Enter the income you expect and read the result against the latest brackets shown, keeping some room below a line: the brackets usually rise a little with inflation each year.
How it's calculated
Medicare's income measure is your modified adjusted gross income: adjusted gross income plus tax-exempt interest, plus four exclusions added back (foreign earned income, savings bond interest used for college, and income from Puerto Rico or three U.S. territories). Social Security takes it from your return for the tax year two years before the premium year, compares it with the premium year's brackets for your filing status, and adds a fixed amount to each premium.
There are three sets of brackets. Single filers, heads of household, qualifying surviving spouses and married people who filed separately and lived apart all year use one. A joint return uses brackets twice as high, except the top one, which is 1.5 times as high. Married people who file separately and lived together at any time in the year use a third set with only two brackets, the two highest.
An example
Say you file single and your 2024 adjusted gross income was $120,000, with no tax-exempt interest. That is over $109,000 and not over $137,000, so for 2026 you are in the first bracket. Your Part B premium is $284.10 a month instead of the standard $202.90, a surcharge of $81.20, and your drug coverage costs $14.50 a month more than your plan's premium. Together that is $95.70 a month, $1,148.40 for the year. You are $17,000 below the second bracket, which would add another $1,736.40 a year.
A married couple filing jointly with twice that income, $240,000, is in the same bracket on the joint table, and both pay the surcharge: $2,296.80 a year for the two of them. Another $40,000 of income, to $280,000, would move them to bracket 2 and $5,769.60 a year. The same $120,000 on a separate return, living together, costs $6,355.20 a year, because that table goes straight to the second-highest bracket.
Late-enrollment penalties
If you signed up for Part B late, your premium rises by 10% of the standard premium for each full 12 months you could have had it, for as long as you have Part B. The penalty is on the standard premium only, never on the surcharge, and the whole premium is rounded to the nearest 10 cents. Two years late in 2026 makes your Part B premium $243.50. The Part D penalty is 1% of the national base premium ($38.99 in 2026) for each month counted on your plan's penalty notice (months without creditable drug coverage after your first chance to enroll), rounded to the nearest 10 cents: 14 months adds $5.50 a month to your plan's premium.
Assumptions and limits
- Premiums are for a full year on Part B: 12 times the monthly amount. If you join partway through the year, you pay for the months you are enrolled.
- The Part B premium is the standard premium. Anyone who pays IRMAA pays the full standard premium. Some people with no surcharge pay less than the standard premium because a small Social Security increase cannot cover a larger premium increase; the calculator does not model that.
- The income is what you enter for the return two years before the premium year. Social Security uses what the IRS sends it: that return, or the one from three years back until the later one is processed.
- A married person who files separately is priced alone; your spouse's premiums depend on their own return. Social Security assumes separate filers lived together unless told otherwise.
- If you did not file a return for that year and the IRS reports income above the threshold, Social Security charges the top bracket until you show otherwise. The calculator assumes you filed.
- Years are listed only once Medicare has published their figures. The calculator does not estimate future brackets or premiums.
- It does not work out adjusted gross income from your sources of income, decide an appeal, or model a Medicare Advantage plan's reduction of the Part B premium, Part B coverage of immunosuppressive drugs only, Part A premiums, help from Medicare Savings Programs or Extra Help, or relief from a penalty under a special enrollment period.
Input field details
What to enter in each box, where to find the number, and how this calculator treats it. When two calculators give different answers from the same numbers, it's usually because they handle one of these differently.
Filing status
The status on the tax return two years before the premium year (for example, your 2024 return for 2026 premiums).
Where to find itThe filing status box at the top of Form 1040.
How this tool treats itSingle, head of household and qualifying surviving spouse use one bracket table, and a joint return uses another with thresholds twice as high (the top one is 1.5 times). Married people filing separately who lived together at any time that year use a third table, where the surcharge jumps straight to the fourth bracket above the first threshold. If you filed separately and lived apart all year, the single table applies, but Social Security assumes you lived together until you tell it otherwise with a signed statement.
Adjusted gross income
The adjusted gross income on that return.
Where to find itForm 1040, line 11, on that return.
How this tool treats itIt already includes the taxable part of your Social Security, IRA and 401(k) withdrawals, a Roth conversion, capital gains and wages. Tax-free Roth withdrawals and the untaxed part of Social Security are not in it and do not count. If line 11 is negative, enter 0 here and subtract the loss from your tax-exempt interest (not below 0), because Medicare adds the two together.
Allowed range$0 to $10,000,000
Tax-exempt interest
Interest that was not taxed, such as municipal bond interest.
Where to find itForm 1040, line 2a.
How this tool treats itMedicare adds it to adjusted gross income, so it can push you into a bracket even though it was not taxed.
Allowed range$0 to $5,000,000
Excluded income added back
Income left out of adjusted gross income under four exclusions: foreign earned income and housing, U.S. savings bond interest used for college, and income from Puerto Rico, Guam, American Samoa or the Northern Mariana Islands excluded from the return.
Where to find itForm 2555 (foreign earned income), Form 8815 (savings bond interest), or Form 4563 and the Puerto Rico exclusion.
How this tool treats itMedicare adds these back, along with tax-exempt interest. Most people have none and leave it at 0.
Allowed range$0 to $5,000,000
Both of us are on Part B
On a joint return, whether both of you are enrolled in Medicare Part B in the premium year.
How this tool treats itEach spouse on Part B pays the surcharge, and both are priced at the joint return’s bracket, so a couple’s cost is twice one person’s.
Medicare drug coverage
Whether you (and your spouse) have a Medicare Part D plan or a Medicare Advantage plan that includes drug coverage. A retiree drug plan counts only if it is a Medicare Part D plan; your plan’s notices say so.
How this tool treats itAnyone with Medicare drug coverage pays the Part D surcharge at the same bracket, whichever kind of plan it is. It is billed by Medicare or taken from your Social Security payment, not added to the plan’s bill. Without Medicare drug coverage there is no Part D surcharge. VA, TRICARE or other drug coverage that is not a Medicare plan does not count here.
Drug plan premium
The monthly premium your drug plan charges, before any surcharge. Leave it at 0 to see Medicare’s part only.
Where to find itYour plan’s Annual Notice of Change or your premium bill.
How this tool treats itPlans set their own premiums, so the calculator adds the one you enter rather than estimating it.
Allowed range$0 to $1,000 a month
Years late for Part B
The number of full 12-month periods you could have had Part B but did not, as counted on your Social Security notice. A 20% penalty is 2.
Where to find itThe premium notice from Social Security, which states the penalty as a percentage.
How this tool treats itThe penalty is 10% of the standard Part B premium for each full 12-month period, for as long as you have Part B. It is not charged on the surcharge. The whole premium is then rounded to the nearest 10 cents, with 5 cents rounding up.
Allowed range0 to 45
Not includedWhich months count is Social Security’s decision. Months covered by a group health plan through your or your spouse’s current job generally do not.
Months without drug coverage
The number of months your plan counted as uncovered when it set your Part D penalty.
Where to find itThe late enrollment penalty notice from your drug plan.
How this tool treats itThe penalty is 1% of the national base beneficiary premium for each month, rounded to the nearest 10 cents. The base premium changes each year, so the penalty does too.
Allowed range0 to 250
Questions
What income does IRMAA use?
Why is it based on income from two years ago?
Is IRMAA a cliff?
Can I appeal IRMAA?
What if we file separately?
Does IRMAA apply with Medicare Advantage?
When are the brackets for next year published?
Version history
- September 28, 2026 (version 1.0.0): First version. Your Medicare IRMAA surcharge for Part B and Part D, for one person or a couple, with the separate-return brackets, the distance to the next bracket, late-enrollment penalties and your whole premium, for 2025 and 2026.