Medicare Advantage vs. Medigap

Medicare Advantage and Medigap are two different ways to round out Medicare coverage, and you generally cannot use both at the same time. This page explains how each works so the choice between them is clearer.

At a glance

Medicare Advantage vs. Medigap — At a glance
	Medicare Advantage (Part C) MA	Medigap (Supplement) Medigap
How it works	A private plan that replaces Original Medicare and bundles your coverage	A policy that pays some out-of-pocket costs left by Original Medicare
Provider access	Usually a network such as an HMO or PPO; referrals may be needed	Any provider nationwide that accepts Original Medicare
Drug coverage	Often included as built-in Part D	Not included; you buy a separate Part D plan
Out-of-pocket limit	Yes; plans cap your annual in-network covered costs	No formal cap, but the policy covers most cost-sharing
Extra benefits	May include dental, vision, hearing, and more	Standardized medical cost-sharing only

Two different structures

Medicare Advantage, also called Part C, is a private plan that replaces Original Medicare and delivers your Part A and Part B benefits, usually through a network of doctors and hospitals. Many plans bundle in drug coverage and extras and cap your annual out-of-pocket spending.

Medigap, also called a Medicare Supplement, works alongside Original Medicare rather than replacing it. It pays much of the cost-sharing that Original Medicare leaves behind, such as coinsurance and deductibles, and lets you see any provider that accepts Medicare nationwide.

California's birthday rule

California uses a birthday rule that gives Medigap policyholders a yearly window around their birthday to switch to an equal or lesser Medigap plan without new medical underwriting.

Where to find it in your policy

The Summary of Benefits

A Medicare Advantage plan's Summary of Benefits outlines copays, the out-of-pocket maximum, and which extra benefits are included.

The Evidence of Coverage

The Evidence of Coverage is the detailed document that explains rules for referrals, prior authorization, and what happens when you go out of network.

The provider directory or formulary

The plan's provider directory shows which doctors are in network, and the formulary lists covered drugs and their tiers.

What it looks like on a real claim

Example 1 — Seeing an out-of-area specialist

You travel out of state and want to see a specialist there.

Medicare Advantage (Part C)

May not cover the visit unless it is an emergency, since the specialist is outside the network.

Medigap (Supplement)

Covers the visit as long as the specialist accepts Medicare, because there is no network.

Example 2 — A hospital stay

You are admitted for a three-day hospital stay.

Medicare Advantage (Part C)

You pay the plan's per-day or flat hospital copays up to the annual out-of-pocket cap.

Medigap (Supplement)

The policy pays the Part A coinsurance and deductible, so little or nothing is left for you.

The bottom line

Medicare Advantage and Medigap represent two paths: one bundles coverage into a single private plan with a network and a spending cap, and the other supplements Original Medicare for broad provider freedom.

Because you generally cannot combine them, reviewing each plan's official documents against how you actually use care is the surest way to understand the trade-offs.

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