Medicare Part C (Medicare Advantage) costs most enrollees $0 per month beyond the standard Part B premium, while Part D prescription drug coverage carries a national base premium of $36.78 per month in 2025. Your actual costs for both depend on the specific plan you choose, your income, and how you use your coverage throughout the year.
Medicare Part C (Advantage) Premiums
Medicare Advantage plans bundle hospital, medical, and often drug coverage into a single plan run by a private insurer. In 2025, 76% of Medicare Advantage enrollees are in plans that charge no additional premium beyond the standard Part B premium ($185 per month in 2025). When you factor in both $0-premium plans and those that do charge extra, the average premium across all enrollees comes out to just $13 per month.
That $13 average can be misleading, though. It’s weighted by enrollment, meaning the most popular plans tend to be the cheapest ones. If you pick a plan with richer benefits or a broader provider network, you could pay $50 to $150 or more per month on top of your Part B premium. You still pay Part B no matter what, so the true minimum monthly cost of a Medicare Advantage plan is the Part B premium itself.
Some Medicare Advantage plans actually reduce your costs below Original Medicare through what’s called a “Give Back Benefit.” These plans use a portion of the federal payment they receive to cover part or all of your Part B premium, effectively putting money back in your pocket each month. The amount varies by plan and is listed in the plan’s Summary of Benefits.
Medicare Part D Premiums
Part D covers prescription drugs either as a standalone plan (paired with Original Medicare) or as part of a Medicare Advantage plan that includes drug coverage. The national base beneficiary premium for Part D is $36.78 per month in 2025. This base figure is an average used for penalty calculations, not a price tag you’ll necessarily see. Actual plan premiums vary widely depending on your location, the insurer, and the drugs covered. Some plans charge under $10, others well over $50.
If your Medicare Advantage plan already includes drug coverage, Part D is built into whatever premium that plan charges. You don’t pay separately for it.
Deductibles and Out-of-Pocket Limits
Part D plans can charge an annual deductible of up to $615 in 2026, though many plans set it lower or waive it entirely. After the deductible, you typically pay copays or coinsurance for each prescription until you hit the annual out-of-pocket cap.
Starting in 2025, a major change took effect: Part D now has a hard $2,000 annual cap on out-of-pocket drug spending. Before this, people taking expensive medications could pay thousands more, especially once they entered the old “coverage gap” or donut hole. The $2,000 cap, created by the Inflation Reduction Act, eliminates that gap and protects against catastrophic drug costs. Once you’ve spent $2,000 in a calendar year, your plan covers the rest.
Medicare Advantage plans also have annual out-of-pocket maximums for medical services (separate from the drug cap), which vary by plan but are regulated by CMS.
Income-Related Surcharges (IRMAA)
Higher-income enrollees pay more for Part D through a surcharge called IRMAA, based on your tax return from two years prior. For 2026 coverage, Social Security looks at your 2024 income. The surcharges are added on top of whatever your plan charges.
For single filers:
- $109,001 to $137,000: extra $14.50/month
- $137,001 to $171,000: extra $37.50/month
- $171,001 to $205,000: extra $60.40/month
- $205,001 to $499,999: extra $83.30/month
- $500,000 or more: extra $91.00/month
For married couples filing jointly, the thresholds are roughly double: $218,001 to $274,000 for the first tier, scaling up to $750,000 or more for the highest surcharge. If you’re married filing separately, the brackets are compressed, starting at $109,001 with fewer tiers.
If your income has dropped significantly since the tax year being used (due to retirement, divorce, or other life changes), you can appeal the surcharge by filing a request with Social Security.
Late Enrollment Penalties
If you don’t sign up for Part D when you’re first eligible and go 63 or more consecutive days without creditable drug coverage, you’ll face a permanent penalty. The math: 1% of the national base beneficiary premium for every month you went without coverage. In 2026, the base premium is $38.99, so someone who delayed 14 months would pay an extra $5.50 per month, added to their plan premium, for as long as they have Part D.
This penalty recalculates each year as the base premium changes, so it can inch up over time. It’s one of the strongest reasons to enroll in Part D even if you take few or no medications.
Help for Lower-Income Enrollees
Medicare’s “Extra Help” program (also called the Low-Income Subsidy) can dramatically reduce Part D costs, covering most or all of the premium, deductible, and copays. In 2026, you may qualify if your annual income is below $23,940 as an individual or $32,460 as a married couple, with resources (savings, investments, real estate other than your home) under $18,090 for individuals or $36,100 for couples.
Eligibility is determined by Social Security, and you can apply at any time during the year. People who qualify typically pay no more than a few dollars per prescription.
Putting the Total Costs Together
Your combined monthly cost depends on the path you choose. Someone on Original Medicare with a standalone Part D plan might pay the $185 Part B premium plus $20 to $60 for Part D, landing around $205 to $245 per month before any drug copays. Someone on a $0-premium Medicare Advantage plan with built-in drug coverage could pay just the $185 Part B premium, though they’ll face copays and coinsurance when they use services.
The cheapest option on paper isn’t always the cheapest in practice. A $0-premium Advantage plan with high copays for specialists or hospital stays can cost more overall than a plan with a $30 monthly premium and lower cost-sharing. When comparing plans, the most useful number is estimated total annual cost, including premiums, deductibles, and the copays you’d expect based on the medications you take and the doctors you see. Medicare’s Plan Finder tool at medicare.gov calculates this when you enter your prescriptions and providers.