Part B Premium Calculator: Estimate Your Medicare Cost

A Part B premium calculator estimates the monthly Medicare Part B premium you may owe based on your coverage year, income, tax filing status, and any applicable adjustment. Entering those details can produce an estimate, but the exact amount depends on current Medicare figures and your official income determination.

Formula

This estimate uses a simplified version of the income-related monthly adjustment amount (IRMAA) method. The standard premium and income brackets are set for each year, so a fully current calculator needs the official figures for that coverage year. Because this page’s calculator inputs do not contain the year-specific bracket table or surcharge amounts, it cannot calculate a reliable personalized premium from the year and income alone. The calculator block is therefore only a basic input specification, not a functional premium calculation; consult the current official Medicare premium table to determine the applicable amount.

For a valid calculation, the general structure is:

Estimated monthly Part B premium = standard monthly premium + applicable monthly IRMAA

• Standard monthly premium: the base Part B amount for the selected coverage year, in U.S. dollars per month.
• Modified adjusted gross income (MAGI): generally the income measure Medicare uses for IRMAA, based on a federal tax return, in U.S. dollars per year.
• Filing status: the tax filing category used to select an income threshold.
• IRMAA: an additional monthly amount, if the applicable income bracket requires one.

Income brackets are not a continuous percentage formula. They work as steps: crossing a threshold can move someone into a higher surcharge tier. The precise thresholds and surcharges depend on the coverage year and filing status. The 2026 standard premium shown in the input example should be checked against the current official figures before use; a calculator should not treat a default or illustrative amount as a guaranteed bill.

Worked Example

The block provides these default entries: coverage year 2026, standard monthly premium $202.90, MAGI $100,000, and individual filing status. These values do not identify the applicable surcharge without the official 2026 income-bracket table. Therefore, a precise result cannot be calculated from the supplied fields alone. To complete the example, look up the 2026 bracket for an individual with the relevant MAGI, add that bracket’s monthly IRMAA to the year’s standard premium, and round only as the official figures specify. This is an important limitation, not a reason to guess an amount.

What Part B Premiums Cover

Medicare Part B is the portion of Original Medicare that generally helps cover medically necessary services and preventive services, including physician and outpatient care. Most people pay a monthly premium for Part B, even when the premium is deducted from a Social Security benefit rather than paid as a separate bill.

The premium is not the same as total health-care spending. Part B beneficiaries may also face an annual deductible and cost sharing for covered services. A premium calculator estimates only the premium; it does not predict deductibles, coinsurance, uncovered services, prescription costs, or expenses from other coverage.

How Income Affects the Estimate

Most people pay the standard premium. People with income above the relevant threshold may pay IRMAA, an additional amount on top of the standard premium. Medicare generally uses tax information from two years earlier to determine IRMAA. For example, a premium year commonly uses an earlier tax return, so a recent change in income may not immediately appear in the initial determination.

When estimating, gather:

• The coverage year for which you want the estimate.
• Your filing status for the tax return Medicare uses.
• Your modified adjusted gross income from that return.
• The official standard premium and IRMAA thresholds and amounts for that coverage year.

Do not assume that household income can simply be divided in half, or that a small income increase creates a surcharge equal to that increase. Brackets are tiered, and the relevant filing-status rules matter. Married people who file separately may be subject to a different bracket structure from people filing jointly.

Using a Calculator Carefully

A useful calculator should state its coverage year, identify the source and date of its premium and bracket data, and distinguish the standard premium from IRMAA. If it asks only for an income figure but not the year and filing status, it cannot reliably select the right bracket.

Check these points before relying on an estimate:

• Enter annual income in the units requested; do not enter a monthly amount as annual income.
• Use the MAGI figure and tax year specified by the calculator, rather than wages alone or take-home pay.
• Select the applicable filing status. Do not use the joint threshold for an individual return.
• Confirm whether the result is monthly or annual. Multiply a monthly estimate by 12 only when you need a simple yearly premium total.
• Check whether the estimate includes IRMAA and whether it covers Part B alone or combines other Medicare charges.

Rounding can also cause apparent differences. Official premiums and surcharges are stated as dollar amounts per month; estimates may display cents or round to whole dollars. A small display difference does not necessarily mean the underlying bracket selection is wrong, but a different bracket or coverage year can materially change the estimate.

When an Estimate May Not Match Your Bill

The Social Security Administration or another responsible agency makes the official determination. A calculator cannot account for every administrative detail, and its result is not a bill or a guarantee. Your amount can differ if the calculator uses outdated figures, the wrong filing status, an incorrect income year, or an incomplete income measure.

If your income has fallen because of a qualifying life-changing event, such as retirement or a reduction in work, you may be able to ask for an IRMAA review using the appropriate process and documentation. A calculator cannot decide whether a change qualifies or replace that review. Check current agency instructions for the applicable form, eligible events, and evidence requirements.

Also keep Part D separate in your calculations. Part D prescription drug coverage can have its own income-related adjustment, but that is not part of the Part B premium. Likewise, Medicare Advantage plan premiums and other coverage costs are separate expenses.

Frequently Asked Questions

How do I calculate my Medicare Part B premium?
Find the standard premium for your coverage year, determine whether your MAGI and filing status place you in an IRMAA bracket, and add that bracket’s monthly surcharge if applicable. Use the current official table for exact amounts.

Which year’s income does Medicare use for Part B IRMAA?
Medicare generally uses tax information from two years before the premium year. If your circumstances have changed substantially, check whether you can request a review rather than assuming the older return will always determine your final amount.

Does the Part B premium calculator include the deductible?
No. A Part B premium estimate is the recurring monthly premium. The annual deductible and any coinsurance are separate cost-sharing amounts.

Is IRMAA based on gross income or taxable income?
IRMAA generally uses modified adjusted gross income, which is not necessarily the same as wages, gross income, or taxable income. Use the income definition and tax-return year stated in current official guidance.

Can my Part B premium change during the year?
Premium amounts and determinations can change under applicable rules, and an adjusted determination may follow a review or updated information. Check notices from the responsible agency and current Medicare guidance for your situation.

Is a calculator’s result the amount I will definitely pay?
No. Treat it as an estimate. The official premium determination, based on the applicable year, income information, filing status, and agency rules, controls the amount billed or deducted.

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in year | Coverage year | year | 2026 | 2000
in premium | Standard monthly premium | USD/month | 202.90 | 0
in income | Modified adjusted gross income | USD/year | 100000 | 0
sel filing | Tax filing status | Individual=1, Joint=2, Married filing separately=3