Medicare is one program with four lettered pieces, and the letters are not a sequence. You do not graduate from A to B to C to D. You pick a combination, and the combination you pick determines what you pay for the rest of your life in some cases.
The numbers below are the current official 2026 figures from CMS’s November 14, 2025 premiums and deductibles fact sheet and Medicare.gov, with the 2027 figures noted where CMS has already announced them. Open enrollment for plan year 2027 runs October 15 to December 7, 2026, so both sets matter right now.
The Four Parts at a Glance
| Part | What it covers | What it costs in 2026 | How you get it |
|---|---|---|---|
| Part A | Inpatient hospital, skilled nursing facility, hospice, some home health | $0 premium for about 99% of enrollees; $1,736 deductible per benefit period | Automatic if you get Social Security; otherwise you sign up |
| Part B | Doctors, outpatient care, durable medical equipment, most preventive services | $202.90/month standard premium, $283 annual deductible, then 20% coinsurance | You enroll and pay monthly, usually deducted from Social Security |
| Part C | Everything A and B cover, usually D too, plus extras | $0 to modest plan premium on top of the Part B premium; in-network costs capped at $9,250 | You join a private Medicare Advantage plan instead of using Original Medicare |
| Part D | Outpatient prescription drugs | Average $36/month standalone plan, deductible up to $615, $2,100 out-of-pocket cap | Standalone drug plan or bundled into a Medicare Advantage plan |
Part A
Part A is hospital insurance. Medicare.gov describes it as covering inpatient care in hospitals, skilled nursing facility care, hospice care and home health care.
CMS reports that approximately 99% of beneficiaries pay no Part A premium because they have at least 40 quarters of Medicare-covered employment. If you have 30 to 39 quarters, or were married to someone who did, you can buy in at $311 a month in 2026. With fewer than 30 quarters, the full premium is $565 a month, up $47 from 2025.
Premium-free does not mean free. The 2026 inpatient hospital deductible is $1,736 per benefit period, up $60 from $1,676 in 2025, and it covers your share of the first 60 days. After that you pay $434 a day for days 61 through 90 and $868 a day for lifetime reserve days. Skilled nursing facility coinsurance is $217 a day for days 21 through 100.
That deductible resets per benefit period, not per year, so two separate hospitalizations months apart can each carry a full $1,736.
Part B
Part B is medical insurance: physician services, outpatient hospital care, certain home health services, durable medical equipment, and most preventive services including shots and the annual wellness visit.
The standard 2026 premium is $202.90 a month, an increase of $17.90 from $185.00 in 2025. The annual deductible is $283, up from $257. After the deductible, the Medicare and You 2026 handbook says you usually pay 20% of the Medicare-approved amount for Part B services, with no ceiling.
Higher earners pay more. CMS’s 2026 income-related monthly adjustment amounts start above $109,000 in modified adjusted gross income for individuals and $218,000 for joint filers, pushing the total Part B premium as high as $689.90 a month at the top bracket. About 8% of Part B enrollees pay a surcharge.
Delaying Part B without other qualifying coverage costs 10% of the premium for each full 12 months you could have enrolled and did not, permanently. See the late enrollment penalty math.
Part C (Medicare Advantage)
Part C is not extra coverage. It is a different delivery method. A private plan approved by Medicare provides your Part A and Part B benefits, usually adds Part D, and typically adds extras Original Medicare does not cover.
The tradeoffs are network and rules. Medicare.gov notes you may need to use in-network doctors and get prior approval for certain drugs and services. In exchange you get an out-of-pocket ceiling Original Medicare does not have.
CMS’s MOOP calculations set the mandatory in-network limit at $9,250 for 2026, down $100 from $9,350 in 2025, and $9,850 for 2027. The combined in-network and out-of-network limit, which applies to PPOs, is $13,900 in 2026 and $14,800 in 2027. Plans can go lower, and most do: KFF puts the average 2026 in-network out-of-pocket limit at $5,421.
KFF also reports that 75% of enrollees in individual Medicare Advantage drug plans pay no premium beyond the Part B premium in 2026, with an average supplemental premium of $15 a month across all enrollees. Read the full comparison in Medicare Advantage vs Original Medicare.
Part D
Part D covers outpatient prescription drugs through private plans. Medicare.gov’s 2026 rules: no plan may set a deductible above $615, you pay 25% coinsurance in the initial coverage stage, and once your out-of-pocket spending on covered drugs reaches $2,100 you pay nothing for the rest of the year.
CMS’s CY 2027 Rate Announcement raises the deductible cap to $700 and the out-of-pocket threshold to $2,400 for 2027. The national base beneficiary premium, which drives the late enrollment penalty, moves from $38.99 to $41.33.
KFF’s 2026 analysis puts the average standalone drug plan premium at $36 a month and the average drug premium inside a Medicare Advantage plan at $8. Insulin is capped at $35 for a one-month supply of each covered product, and ACIP-recommended adult vaccines cost $0. Full detail lives in the Part D guide and the cost breakdown, and plan-by-plan coverage differences come down to the formulary.
What Medicare Does Not Cover
The Medicare and You 2026 handbook lists items Original Medicare does not cover, and the list surprises people every year:
- Long-term care, including nursing home and in-home personal care assistance with dressing, bathing and using the bathroom
- Eye exams for prescription glasses or contact lenses
- Hearing aids and the exams to fit them
- Routine physical exams
- Cosmetic surgery and massage therapy
- Concierge or retainer-based medicine
- Most dental care, including routine cleanings, fillings, extractions and dentures
The handbook does note narrow exceptions, such as dental work closely tied to a covered procedure like a heart valve repair, an organ transplant or cancer treatment. See Medicare dental coverage for where those lines actually fall. Medicare Advantage plans often add vision, hearing and dental benefits, but the annual dollar allowances are usually modest. For long-term care specifically, Medicaid is the payer of last resort, which is why Medicaid vs Medicare matters for anyone planning ahead.
How the Parts Get Combined in Real Life
There are really only two workable packages.
Original Medicare plus Medigap plus a Part D plan. You keep Parts A and B, buy a Medicare Supplement policy to absorb the 20% coinsurance and the hospital deductible, and add a standalone drug plan. You can see any provider who accepts Medicare, anywhere in the country, with no networks and no prior authorization for Part A and B services. The cost is three premiums: $202.90 for Part B, a Medigap premium, and a drug premium averaging $36.
The catch is timing. Your six-month Medigap open enrollment period starts when you are 65 and enrolled in Part B, and that is the one window where insurers cannot deny you or price you up for health history in most states. Miss it and you may not be able to switch back later. Compare Medigap premiums and the most popular option, Plan G, before that window closes.
A single Medicare Advantage plan with drug coverage. One card, one plan, often a $0 supplemental premium, a hard in-network ceiling of $9,250 in 2026, and extras Original Medicare does not cover. You still pay the $202.90 Part B premium. You accept a network, prior authorization, and the reality that your plan’s benefits and provider list can change each January.
Which one wins depends on how much you travel, whether your specialists are in network, and how much variable risk you can absorb. Medicare Advantage vs Medigap works through the tradeoff.
The Bottom Line
Part A is the hospital piece and is usually free but carries a $1,736 deductible. Part B is the doctor piece at $202.90 a month plus $283 and 20% with no ceiling. Part C replaces both with a private plan that caps in-network spending at $9,250. Part D handles drugs with a $2,100 ceiling in 2026 and $2,400 in 2027.
The expensive mistake is not picking the wrong plan. It is missing your Medigap window or your Part D enrollment window and paying a permanent penalty. If your income is limited, check the Medicare Savings Programs first, since they can pay your Part B premium outright.