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Medicare Supplement (Medigap) Explained

How it works and how to pick a plan.

Medigap fills the gaps in Original Medicare — the deductibles and coinsurance it doesn't pay. Plans are standardized, so the same letter means the same coverage at every insurer. Here's how to choose.

How Medigap works

You keep Original Medicare and add a Medigap policy that pays your share of covered costs. You see any doctor that takes Medicare, with little or no surprise billing. You add a separate Part D drug plan.

Plan G vs Plan N vs F

Plan G is the popular pick for new enrollees — it covers nearly everything except the small Part B deductible. Plan N trims the premium with minor copays. Plan F (closed to newcomers) covered everything. Compare them in the plan comparison.

What it costs

Because coverage is standardized, price is the main variable — typically $100–$300/month by plan, age and state. Shop the same letter across insurers; the cheapest reputable one usually wins. Estimate with the cost calculator.

Medigap vs Advantage

Medigap costs more monthly but makes care predictable and lets you go anywhere; Advantage is cheaper upfront but uses networks and copays. Compare total cost in the Medigap vs Advantage calculator.

The window that matters most

For 6 months after your Part B starts, you can buy any Medigap plan with no health questions. Miss it and insurers can deny you or charge more. Find your window with the open enrollment calculator.

Educational only — not connected with Medicare and not insurance advice. Confirm at Medicare.gov.