Most Medicare beneficiaries pay at least $185 per month in 2025 for their Part B premium alone, but total costs vary widely depending on which parts of Medicare you have, whether you add supplemental coverage, and how much healthcare you actually use. There’s no single “average cost” because Medicare is built from several distinct pieces, each with its own premiums, deductibles, and cost-sharing. Here’s what each piece costs and what you can realistically expect to spend.
Part A: Hospital Coverage
Most people pay $0 per month for Part A because they or a spouse paid Medicare taxes for at least 10 years (40 work quarters). If you don’t meet that threshold, Part A premiums can run several hundred dollars a month.
Even with premium-free Part A, hospital stays come with significant cost-sharing. Each time you’re admitted (per “benefit period”), you pay a deductible before Medicare covers anything. Once you’ve been in the hospital longer than 60 days, daily coinsurance kicks in at $434 per day for days 61 through 90. If your stay extends beyond 90 days, you start drawing from a lifetime reserve of 60 extra days at $868 per day. Once those lifetime reserve days are used, they don’t reset. For most people who have short or no hospital stays in a given year, Part A costs very little out of pocket. But a single extended hospitalization can add thousands.
Part B: Doctor Visits and Outpatient Care
Part B covers physician visits, outpatient procedures, lab work, preventive screenings, and durable medical equipment. The standard monthly premium in 2025 is $185.00, which most people pay either through automatic deduction from their Social Security check or by direct billing. On top of that, there’s an annual deductible of $257 before Medicare starts covering its share.
After you meet the deductible, Part B generally covers 80% of approved services, leaving you responsible for the remaining 20% with no cap on how much that 20% can add up to. This open-ended cost-sharing is a major reason many people buy supplemental insurance.
Higher Premiums for Higher Earners
If your modified adjusted gross income from two years prior exceeds certain thresholds, you’ll pay more than the standard $185. These income-related monthly adjustment amounts (IRMAA) add surcharges on top of the base premium for both Part B and Part D. The surcharges are tiered, so someone just above the first income threshold pays moderately more, while the highest earners can pay several times the standard premium.
Part D: Prescription Drug Coverage
Part D premiums depend entirely on which plan you choose. Plans vary by region, formulary, and pharmacy network, so there’s no single national premium. What is standardized is the maximum deductible a plan can charge: $590 in 2025, rising to $615 in 2026.
The biggest recent change to Part D is the introduction of a $2,000 annual cap on out-of-pocket spending for covered prescriptions. Before this cap, people taking expensive specialty medications could face costs of $10,000 or more per year in the coverage gap. The new limit means that once you’ve spent $2,000 out of pocket on covered drugs in a calendar year, you pay nothing more for the rest of that year. Medicare also allows you to spread that $2,000 across monthly payments rather than paying it all upfront when you fill expensive prescriptions early in the year.
Medicare Advantage (Part C)
Medicare Advantage plans are private insurance alternatives that bundle Part A, Part B, and usually Part D into a single plan. They often include extras like dental, vision, hearing, and fitness benefits that Original Medicare doesn’t cover.
The cost picture looks different here. According to KFF, 76% of Medicare Advantage enrollees are in plans with no additional premium beyond the standard Part B premium. When you average across all enrollees, including those in plans that do charge extra, the enrollment-weighted average premium is just $13 per month on top of Part B. That makes Advantage plans appear inexpensive upfront, but they use copays, coinsurance, and network restrictions to manage costs. Every Advantage plan has a maximum out-of-pocket limit for in-network services, which provides a financial ceiling that Original Medicare lacks.
Medigap: Supplemental Insurance
If you stick with Original Medicare (Parts A and B), Medigap policies fill in the gaps, covering things like the 20% Part B coinsurance, hospital deductibles, and excess charges. Plan G is the most popular option for new enrollees and covers nearly all cost-sharing except the annual Part B deductible.
Medigap premiums vary widely by insurance company, your age, your location, and how the insurer prices its policies. Two companies selling identical Plan G coverage in the same zip code can charge very different amounts. Monthly premiums commonly range from around $100 to over $300, though they can be higher in expensive metro areas or for older enrollees. The tradeoff is predictability: with Medigap, your out-of-pocket exposure for covered services drops to near zero, which makes healthcare spending much easier to budget.
Putting the Full Picture Together
For someone on Original Medicare with a Part D plan and no supplemental coverage, the baseline annual cost in 2025 looks roughly like this:
- Part B premiums: $2,220 per year ($185 x 12)
- Part B deductible: $257 per year
- Part D premiums: varies by plan, commonly $300 to $600+ per year
- Part D deductible: up to $590 per year
- Cost-sharing on services and drugs: varies with usage
That puts the floor at roughly $2,800 to $3,100 per year in premiums and deductibles alone, before you pay a single copay or coinsurance charge. Add a Medigap plan and you might spend $4,000 to $6,500 or more annually in total premiums, but with far less risk of a surprise bill from a major health event. Choose Medicare Advantage instead, and your premium costs may be lower upfront, but you’ll pay copays and coinsurance as you use services.
Healthcare usage is the biggest variable. A healthy 66-year-old who sees a doctor twice a year and takes one generic medication will spend far less than someone managing multiple chronic conditions or needing a surgery. The 20% coinsurance on Part B services has no annual limit under Original Medicare, which is why a single expensive procedure, like a joint replacement or cancer treatment, can generate thousands in out-of-pocket costs for people without supplemental coverage.
Late Enrollment Penalties
If you don’t sign up for Part B or Part D when you’re first eligible and don’t have qualifying coverage through an employer, you’ll face a permanent penalty added to your premiums for as long as you have Medicare. For Part B, the penalty is an extra 10% of the standard premium for every full 12-month period you delayed. Someone who waited two years past their initial enrollment window would pay a 20% surcharge on top of the standard premium, every month, for life. Part D has a similar structure. These penalties are designed to discourage people from waiting until they get sick to enroll, and they can add up to significant costs over a long retirement.