Medicare IRMAA Calculator (Part B Premium Surcharge)
Estimate your 2026 Medicare Part B premium including the Income-Related Monthly Adjustment Amount (IRMAA) surcharge. Uses official CMS brackets based on your MAGI from two years ago.
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Adjust values to see instant results
Total Monthly Part B Premium
$202.90
Estimated • Based on your inputs
Monthly IRMAA Surcharge
$0.00
Detailed Breakdown
Disclaimer: This calculator provides estimates for informational purposes only. Results should not be considered financial, tax, or legal advice. Consult a qualified professional for your specific situation.
How This Calculator Works
Calculation methodology and assumptions
The Income-Related Monthly Adjustment Amount (IRMAA) is a surcharge CMS adds to the standard Medicare Part B premium ($202.90/month for 2026) for beneficiaries whose Modified Adjusted Gross Income exceeds set thresholds. Critically, IRMAA uses your MAGI from the tax return filed TWO YEARS prior — your 2026 premium is based on your 2024 MAGI, reported to Social Security by the IRS. There are six brackets for single/joint filers and a compressed three-bracket scale for beneficiaries who are married but file separately while living with their spouse (that column jumps straight from the bottom bracket to the two highest ones, with no gradual middle tiers). This calculator models Part B only, using the official 2026 CMS bracket table; the separate Part D IRMAA surcharge (added to your Part D or Medicare Advantage drug plan premium) uses the same MAGI brackets but different, plan-year-specific dollar add-ons announced separately by CMS.
How to Use This Investment & Retirement Calculator
- 1
Enter your initial investment
Input the lump sum you plan to invest today. This is your starting principal that will begin compounding immediately.
- 2
Set your monthly contribution
Enter the amount you plan to add each month. Consistent contributions accelerate growth through dollar-cost averaging.
- 3
Input expected return and time horizon
Set your expected annual return (7–10% for stocks historically, 4–6% for bonds) and investment period. Longer time horizons amplify compounding effects dramatically.
- 4
Review the growth projection
The results show your total invested amount, earnings from compound growth, and a year-by-year projection table showing how your money grows over time.
Example Calculation
How does compound interest build wealth over time?
Starting with $10,000 and adding $500/month at an 8% average annual return for 30 years: Your total contributions would be $190,000 ($10K initial + $180K in monthly deposits). But with compound growth, your portfolio would grow to approximately $745,000.
Result: Compound interest generated $555,000 in earnings on top of your $190,000 in contributions — nearly 75% of the final value came from returns, not deposits. Starting 5 years later would reduce the final amount by roughly $230,000. Time in the market is the most powerful factor in wealth building.
What Affects Your Results
Rate of Return
Even small differences compound massively over time. 7% vs. 8% over 30 years on $100K means a difference of $200K+. Asset allocation drives your expected return.
Time Horizon
Compounding accelerates exponentially. Most of your wealth is generated in the final years — a 30-year investment earns more in its last 5 years than its first 15.
Contribution Consistency
Regular monthly investments (dollar-cost averaging) smooth out market volatility and ensure you're always buying — including during dips when prices are low.
Fees & Expenses
A 1% annual fee vs. 0.1% fee on a $500K portfolio costs you $4,500/year extra. Over 30 years, high fees can consume 25–30% of potential returns. Use low-cost index funds.
Tips & Best Practices
- Start early. Thanks to compounding, $200/month invested from age 25 to 65 at 8% returns grows to ~$700K. Waiting until 35 cuts that to ~$300K — a $400K penalty for the 10-year delay.
- Don't try to time the market. Research consistently shows that time in the market beats timing the market. Missing the 10 best trading days over 20 years can halve your returns.
- Consider tax-advantaged accounts first: 401(k) (especially with employer match), IRA, HSA. These reduce your tax drag — a 25% tax bracket investor keeps more in a tax-deferred account.
- Rebalance annually. If stocks outperform and grow from 80% to 90% of your portfolio, rebalancing back to 80% locks in gains and manages risk.
- Factor in your state's tax treatment of investment income. Some states exempt certain investment income or have lower rates on capital gains.
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StateCalc Team
Editorial Team
The StateCalc team builds free financial calculators using data from official government sources including the IRS, U.S. Census Bureau, BLS, and state revenue departments. All formulas are validated by an automated test suite and cross-referenced against published data.
Our editorial standardsFrequently Asked Questions
What income is used to calculate IRMAA?
IRMAA is based on your Modified Adjusted Gross Income (MAGI) — your AGI plus tax-exempt interest — from the tax return you filed TWO YEARS before the premium year. Your 2026 Medicare premiums are based on the MAGI reported on your 2024 tax return, not your current income. This lag is important for retirees planning Roth conversions or large RMDs, since a high-income year can raise Medicare premiums two years later.
What are the 2026 IRMAA brackets?
For 2026, single filers with MAGI at or below $109,000 (or $218,000 married filing jointly) pay the standard $202.90/month Part B premium with no surcharge. Above that, five progressively higher brackets add $81.20, $202.90, $324.60, $446.30, or $487.00 per month, topping out at a total premium of $689.90/month for MAGI at or above $500,000 (single) or $750,000 (joint).
Can I appeal an IRMAA determination?
Yes. If a "life-changing event" — such as retirement, marriage, divorce, or the death of a spouse — reduced your income after the tax year used to calculate your IRMAA, you can file Form SSA-44 with the Social Security Administration to request a new determination using more recent income instead of automatically paying the higher bracket.
Does IRMAA apply to Part D as well as Part B?
Yes. CMS applies an income-related surcharge to Part D (prescription drug) coverage using the same MAGI brackets shown here, but the dollar add-on amounts are announced separately each year and layer on top of your specific Part D or Medicare Advantage plan's own premium — they are not modeled in this calculator, which covers Part B only.
How can I reduce my future IRMAA bracket?
Because IRMAA looks back two years, the main levers are managing MAGI in the year that will be looked back on: spreading large Roth conversions across multiple years instead of one lump sum, using Qualified Charitable Distributions (QCDs) to satisfy RMDs without raising MAGI, and harvesting capital losses. Run scenarios with this calculator alongside the Roth Conversion and RMD calculators before executing a large one-time transaction.
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