Medicare Advantage or Original Medicare: what the 2027 files show

35,867,214 of the 69,511,516 people with Medicare counted in CMS's September 2026 county file were in a Medicare Advantage plan (52%). For 2027, 5,089 Medicare Advantage plans are offered, 2,255 of those open to everyone with a $0 premium, and the median in-network out-of-pocket limit is $6,550.

How do the two differ?

Who pays the bills

Original Medicare: Medicare pays doctors and hospitals directly. Medicare Advantage: a private plan approved by Medicare does.

Doctors and hospitals

Original Medicare: any provider that takes Medicare. Medicare Advantage: usually the plan's network (HMO), or lower costs inside it (PPO).

Yearly limit on your costs

Original Medicare: none. Medicare Advantage: every plan has an in-network out-of-pocket limit; the 2027 median is $6,550.

Drug coverage

Original Medicare: add a stand-alone Part D plan. Medicare Advantage: most plans include it.

Extra benefits

Original Medicare: none. Medicare Advantage: many plans add dental, vision, hearing or an allowance; some lower the Part B premium.

Your share of a bill

Original Medicare: usually 20% of the Medicare-approved amount after the Part B deductible. Medicare Advantage: the plan's copays and coinsurance.

Approval before care

Original Medicare: in most cases none. Medicare Advantage: the plan may require prior authorization for some services.

Supplemental coverage

Original Medicare: you can add Medigap, employer or union coverage, or Medicaid to help pay your share. Medicare.gov lists Medigap as an add-on to Original Medicare, not to Medicare Advantage.

Switching back later

Leaving Medicare Advantage for Original Medicare is allowed each open enrollment, but buying a Medigap policy then may not be: outside a guaranteed right, an insurer can refuse you, or charge more for past or present health problems. The trial right helps in the first year: if you joined Medicare Advantage when first eligible at 65 and leave within 12 months, you can buy any Medigap policy sold in your state; if you dropped a Medigap policy to join Medicare Advantage for the first time and leave within 12 months, you can get your old policy back if the same insurer still sells it, or else buy Plan A, B, C, D, F, G, K or L (C and F only if you were eligible for Medicare before January 1, 2020).