Turning 65 or already on Medicare, the single most confusing line on your Social Security statement is usually the premium deduction. Part B has a standard rate almost everyone pays, but once your income crosses a threshold, an extra layer called IRMAA (Income-Related Monthly Adjustment Amount) is stacked on top — and the same surcharge hits both Part B and Part D prescription drug plans. This Medicare calculator estimates your 2025 monthly and annual premiums from your MAGI, tax filing status, and the Part D plan you have chosen, so you can budget the real number before the bill arrives.
Enter your numbers and every figure updates instantly. Raise your MAGI upward and watch the IRMAA tier flip, adding tens or even hundreds of dollars to your monthly premium on top of the base $185 Part B standard rate.
How to Use
- Enter your Modified Adjusted Gross Income (MAGI) — your adjusted gross income plus tax-exempt interest. Medicare uses the MAGI from your federal tax return two years before the current plan year, so for 2025 it looks at your 2023 return.
- Pick your Tax Filing Status — choose 0 for Single or Head of Household, 1 for Married Filing Jointly. Single filers face much lower income thresholds than married couples filing jointly; choosing the wrong one will underestimate IRMAA by a full bracket.
- Type your Part D Plan Premium — the monthly cost of the stand-alone prescription drug plan you have selected. If you have a Medicare Advantage plan that already includes drug coverage, enter your Part D-equivalent premium from your plan letter; if you do not have drug coverage, leave this at 0.
- Read the result card: it breaks out the standard Part B premium, the IRMAA surcharge added to Part B, the IRMAA surcharge added to Part D, the total monthly premium, and the annual total.
The calculation uses the 2025 CMS published rates: standard Part B is $185.00 per month, and IRMAA is added on a tiered table depending on your MAGI bracket. This calculator models the full five-tier 2025 IRMAA schedule for both single and joint filers. Filing-joint thresholds are exactly double the single thresholds.
How IRMAA Works
IRMAA is not a tax — it is a higher premium charged to enrollees whose income exceeds a threshold. Social Security looks at your MAGI from two years prior and assigns you to one of six tiers. The moment your income crosses a bracket, the entire surcharge applies, not just the amount over the line. For a single filer in 2025, the first surcharge kicks in at $109,000 of MAGI; by the time income reaches $342,000, the total Part B premium jumps from $185 to $316.50, and Part D carries an extra $71.40 on top of your plan premium.
Because the tier is based on a two-year-old return, a one-time spike — a large Roth conversion, a capital gain from selling a home, or an early withdrawal — can trigger two years of higher premiums. You can request a life-changing event appeal through Social Security if your income dropped after that return was filed (for example, marriage, divorce, retirement, or loss of a pension).
2025 IRMAA Tiers at a Glance
For a single filer (or head of household):
| MAGI bracket | Part B extra | Part D extra |
|---|---|---|
| $0 – $109,000 | $0 | $0 |
| $109,001 – $144,000 | +$18.80 | +$10.20 |
| $144,001 – $183,000 | +$47.00 | +$25.50 |
| $183,001 – $228,000 | +$75.20 | +$40.80 |
| $228,001 – $342,000 | +$103.30 | +$56.10 |
| $342,001 and up | +$131.50 | +$71.40 |
For a married couple filing jointly, every threshold doubles. The first surcharge begins at $218,000, and the top tier begins above $684,000.
Examples
Example 1 — A typical retiree. A single filer with $90,000 MAGI and a $50/month Part D plan pays the standard $185.00 Part B, no IRMAA on either program, and a $50.00 Part D premium. Total monthly premium is $235.00, or $2,820.00 for the year. Because income is under the $109,000 threshold, they are in the base tier.
Example 2 — The first IRMAA cliff. Another single filer earns $120,000 MAGI — just over the $109,000 line. Part B jumps by $18.80 to $203.80, and Part D adds $10.20 on top of the $50 plan premium, bringing Part D to $60.20. Total monthly premium is $264.00, or $3,168.00 annually. Earning $11,000 more cost this retiree an extra $288 per year.
Example 3 — High-income married couple. A couple filing jointly with $600,000 MAGI and a $60 Part D plan lands in tier 4. Part B becomes $288.30 ($185 + $103.30) and Part D becomes $116.10 ($60 + $56.10). Total monthly premium is $404.40, or $4,852.80 per year — more than double the base Part B rate, and that figure does not count the Part B deductible ($257 in 2025) or coinsurance. A joint MAGI above $684,000 would push them into the top tier at $316.50 Part B.
Example 4 — The Roth-conversion trap. A single filer doing a large one-time Roth conversion pushes MAGI to $1,500,000. Even though the conversion is a single event, the 2026 and 2027 premiums will both be at the top tier: Part B $316.50, Part D with a $50 plan is $121.40, for a monthly total of $437.90 and $5,254.80 annually. Spreading Roth conversions across multiple years is the standard planning fix.
FAQ
How is my Medicare Part B premium calculated?
Start with the 2025 standard Part B premium of $185.00 per month, then add the IRMAA surcharge that corresponds to your MAGI tier. If your MAGI is at or below $109,000 (single) or $218,000 (joint), no surcharge applies and you pay exactly $185.00. Higher incomes move you up six possible tiers, all the way to $316.50 per month.
What is IRMAA and how much extra does it cost?
IRMAA stands for Income-Related Monthly Adjustment Amount. It is a surcharge Social Security applies to Part B and Part D when your MAGI exceeds an income threshold. In 2025 the Part B surcharges range from $18.80 to $131.50 per month, and the Part D surcharges range from $10.20 to $71.40 per month, depending on how high your income is.
Which year's income does Medicare use?
Medicare uses the MAGI reported on your federal tax return from two years before the plan year. So your 2025 premium is based on your 2023 tax return. If your income has since dropped, you can file Form SSA-44 to request a new initial determination based on a life-changing event.
Do married couples have higher IRMAA thresholds?
Yes. Married couples filing jointly face exactly double the single-filer thresholds: the base tier goes up to $218,000 instead of $109,000, and the top tier begins above $550,000 instead of $275,000. If you are married but file separately, the rules are different and usually worse — check the Social Security IRMAA page for the separate-filer table.
Does IRMAA apply to Medicare Advantage plans?
IRMAA applies to Part B regardless of whether you have Original Medicare or a Medicare Advantage (Part C) plan. The Part D IRMAA also applies to anyone who has prescription drug coverage, whether through a stand-alone Part D plan or through a Medicare Advantage Prescription Drug (MAPD) plan. The surcharge is paid through Social Security, not billed by the private insurer.
Can I reduce or appeal my IRMAA?
Yes, if you have had a qualifying life-changing event — such as retirement, marriage, divorce, the death of a spouse, or a work stoppage — you can file Form SSA-44 with Social Security to ask them to use your more recent, lower income instead. Otherwise, IRMAA is set by law and cannot be negotiated with your plan.
Disclaimer
This Medicare calculator is provided for informational purposes only and is not medical advice, insurance advice, tax advice, or legal advice. Premium figures reflect published 2025 CMS rates and the official IRMAA thresholds from Medicare.gov; actual premiums, deductibles, and surcharges vary by plan, enrollment date, and individual circumstance. Always confirm your exact premium directly with Social Security or your plan provider, and consult a licensed insurance broker or tax professional before making retirement-income decisions.