IRMAA Calculator

The IRMAA Calculator estimates the income-related monthly adjustment amount added to Medicare Part B and Part D premiums for higher-income beneficiaries, using the premium tables stored in the calculator (the 2026 CMS schedule, which is based on your modified adjusted gross income from two years earlier). Enter MAGI and filing status, and indicate whether you have Part D.

How It Works

IRMAA is a cliff system, not a gradual phase-in. Your MAGI places you in one of six tiers for your filing status; everyone in the tier pays the same Part B premium and the same Part D surcharge, whether they are one dollar or tens of thousands of dollars into the band. The calculator finds your tier, then reports the Part B premium, the Part B and Part D adjustments, the combined monthly increase over the standard premium, the annual surcharge, and how much MAGI room you have before the next cliff.

The 2026 tiers in the calculator (single filers)

| Tier | MAGI above | Part B premium | Part B surcharge | Part D surcharge | |---|---|---|---|---| | Standard | up to $109,000 |$202.90 | $0 |$0 | | Tier 1 | $109,000 |$284.10 | $81.20 |$14.50 | | Tier 2 | $137,000 |$405.80 | $202.90 |$37.50 | | Tier 3 | $171,000 |$527.50 | $324.60 |$60.40 | | Tier 4 | $205,000 |$649.20 | $446.30 |$83.30 | | Tier 5 | $500,000 |$689.90 | $487.00 |$91.00 |

Joint thresholds are double the single figures through Tier 3 ($218,000 /$274,000 / $342,000 /$410,000), with the Tier 5 joint threshold at $750,000. Married filing separately uses its own compressed schedule.

Parameters

| Input | Required | Meaning | |---|---|---| | MAGI | Yes | Modified adjusted gross income from the lookback year | | Filing status | Yes | Single, joint, or married filing separately | | Has Part D | No | Whether the Part D surcharge applies to you |

Worked example

A single retiree has MAGI of $150,000 in the lookback year. That clears the$137,000 Tier 2 threshold but not $171,000, so Tier 2 applies: Part B premium$405.80 a month, made of the $202.90 standard premium plus a$202.90 adjustment, plus a $37.50 Part D adjustment if enrolled. The combined increase is$240.40 a month, $2,884.80 a year, and the retiree has$21,000 of headroom before Tier 3. Note the cliff: at MAGI of $136,999 the same person pays Tier 1 increases of$95.70 a month; one extra dollar of income across the line costs about $1,737 a year in additional premiums.

The two-year lookback and planning around it

Premiums in 2026 are set from the 2024 tax return, which makes IRMAA a planning problem with a two-year fuse. The classic triggers are Roth conversions, large capital gains from a property sale, and the first years of retirement when deferred-compensation payouts land. Because tiers are cliffs, managing MAGI to just under a threshold, bunching income into a single year to sacrifice one year instead of two, or spreading a Roth conversion over several years to stay in a lower tier can each be worth thousands. Life-change events such as retirement, marriage, divorce, or a spouse's death can also justify an appeal to use a more recent year's income instead of the lookback year.

Limitations

The calculator applies the stored 2026 tables to the MAGI you enter. It does not compute MAGI from your return (the Medicare definition adds tax-exempt interest back to AGI), does not model the married-filing-separately schedule's finer steps beyond the stored tiers, and cannot file or evaluate an appeal. Premiums and thresholds are set annually by CMS; confirm the figures for the year you are planning.

Appealing a tier: life-change events

Because premiums rest on a two-year-old return, the system allows appeals when a life-change event makes that return unrepresentative: marriage, divorce, the death of a spouse, stopping or reducing work, losing income-producing property, or receiving a settlement from an employer. A successful appeal substitutes a current-year estimate, which can drop a household a tier or more in the first retirement years, exactly when lookback income (final salary, deferred compensation) is least representative. File promptly with documentation; the appeal adjusts premiums going forward, and discovering the option a year late leaves the overpaid year unrecoverable in most cases.

MAGI levers that actually move tiers

The controllable levers are the timing and size of optional income: Roth conversions sized to stop below the next threshold, capital gains harvested across two tax years instead of one, installment sales that spread a property gain, and qualified charitable distributions from an IRA, which satisfy required distributions without entering AGI at all and are therefore the cleanest lever for charitably inclined retirees. Tax-exempt interest counts toward IRMAA MAGI, so a municipal-bond ladder does not shelter income from this particular calculation, a surprise to many who built one for exactly that purpose.

Frequently Asked Questions

Why does a two-year-old tax return set my premium?

Social Security uses the most recent return the IRS has processed when premiums are set, which is normally the return from two years prior. A life-change event can substitute a newer estimate through an appeal.

Is IRMAA based on taxable income or MAGI?

MAGI as Medicare defines it: adjusted gross income plus tax-exempt interest. Deductions that reduce taxable income do not reduce IRMAA MAGI, which is why some retirees are surprised by a tier.

Can I reduce IRMAA by managing income?

Yes, within the rules: timing Roth conversions, capital gains, and retirement-account withdrawals around the thresholds is standard planning, precisely because crossing a cliff by a small amount is so expensive.