Medicare Advantage vs. Medigap: How to Actually Choose

Every year, millions of people turning 65 — and millions more already on Medicare — face the same fork in the road: Medicare Advantage or Medigap? The names sound similar. The marketing mail makes them sound almost interchangeable. They are not. One rebuilds your coverage inside a private-insurer network; the other pays alongside Original Medicare with no network at all. Picking the wrong one isn't usually a disaster, but it can lock you into higher costs or a narrower doctor list for a long time. Here's how the two actually compare for 2026.

Both options require you to already have Original Medicare — Part A (hospital) and Part B (medical). From there, they solve the same problem — the 20% Original Medicare doesn't cover, plus deductibles and copays — in opposite ways.

Medigap (Medicare Supplement) is an add-on policy from a private insurer that pays some or all of what Original Medicare leaves behind. You keep Original Medicare as your primary coverage and can see any doctor or hospital in the country that accepts Medicare — no referrals, no network.

Medicare Advantage (Part C) replaces Original Medicare's structure entirely. A private insurer takes over your Medicare benefits and delivers them through its own plan — usually with a network, often with a $0 premium, and almost always bundled with a Part D drug plan and extras like dental, vision, and hearing.

Medigap plans are standardized by letter (A, F, G, N, and others) — every insurer's Plan G covers the exact same benefits, so the only real differences between companies are price, customer service, and rate-increase history. Plan G is the most popular choice for new enrollees, since Plan F closed to anyone who became Medicare-eligible on or after January 1, 2020.

Here's what makes Medigap different day-to-day:

• No network. Any provider that accepts Medicare accepts your Medigap plan — including out of state, which matters if you snowbird or travel often.
• No referrals or prior authorization from the Medigap insurer for Medicare-covered care.
• You pay two premiums — the Part B premium ($202.90/month in 2026) plus your Medigap premium — and typically add a standalone Part D drug plan separately.
• Underwriting after your window closes. Your one guaranteed-issue shot is the Medigap Open Enrollment Period — the 6 months starting the month you're 65 and enrolled in Part B. Miss it, and insurers can ask health questions or decline you in most states (a handful of states offer year-round or birthday-rule guaranteed issue).

Medicare Advantage plans bundle hospital, medical, usually drug coverage, and often dental, vision, hearing, and even a fitness benefit into one plan and one card. Many plans carry a $0 monthly premium — you still pay the standard Part B premium, but nothing extra to the plan itself in a lot of cases.

In exchange, MA plans come with more moving parts:

• Networks (HMO or PPO). HMOs generally require you to stay in-network except for emergencies; PPOs allow out-of-network care at a higher cost.
• Referrals and prior authorization are common for specialists, imaging, and certain procedures — an extra step Medigap doesn't require.
• An annual out-of-pocket maximum (Medicare Advantage plans are required to have one; Original Medicare and Medigap don't need one because Medigap already covers most of the gap).
• Guaranteed issue every year. Unlike Medigap, MA plans can't turn you down or charge more for pre-existing conditions during your enrollment window.

There's no universally "better" plan — only the plan that fits how you actually live and how much financial certainty you want to pay for. If you value never getting a surprise bill and want the freedom to see any provider anywhere, Medigap's higher premium buys that peace of mind. If you'd rather keep monthly costs low, want dental and vision built in, and are comfortable working within a network, Medicare Advantage can deliver strong value — as long as you read the Evidence of Coverage, not just the brochure.

The one mistake worth avoiding: picking based on the mailer with the biggest "$0 premium" headline, or the Medigap quote with the lowest number, without checking whether your own doctors and prescriptions actually work well under that specific plan. Timing also matters — the safest window to enroll in Medigap without health questions is the 6 months right after you turn 65 and enroll in Part B, so it's worth deciding before that window closes even if you ultimately choose Medicare Advantage.

Want help comparing your specific options? See our guides on what changes for the 2027 Annual Enrollment Period, how to read your ANOC letter, or visit the Medicare education center.