The choice between Medicare Advantage and Original Medicare is the most consequential decision new Medicare enrollees make — and it is frequently made on incomplete information. A $0-premium Medicare Advantage plan looks free. It is not. An Original Medicare plan with Medigap looks expensive. For heavy utilizers, it often costs less.

This guide compares both options on cost, coverage, and practical usage — so you can make the decision based on your actual healthcare situation.

How Each Option Works

Original Medicare is administered by the federal government. You see any provider in the US who accepts Medicare — no network, no referrals required. Medicare pays 80% of approved costs after the Part B deductible. You pay the remaining 20% with no annual cap unless you have Medigap.

Medicare Advantage (Part C) is administered by private insurers approved by Medicare. These plans must cover everything Original Medicare covers, but deliver it through a managed care model — typically an HMO or PPO with a network of providers. Most plans include Part D drug coverage. Many have $0 premiums and extra benefits like dental, vision, and hearing.

Cost Comparison — The Full Picture

Cost FactorOriginal Medicare + Plan G MedigapMedicare Advantage ($0 premium HMO)
Monthly premium$202.90 (B) + ~$140 (Plan G) + ~$35 (Part D) = ~$378/mo$0 + Part D included typically
Annual deductible$283 (Part B only)$0–$500 (varies by plan)
Out-of-pocket maxNone$3,500–$8,300/yr (required)
20% coinsuranceCovered by MedigapCopays per service ($10–$60)
Specialist visitsNo referral, no networkReferral often required; in-network only
Out-of-network careAny Medicare-accepting providerHigher cost or not covered (HMO)
Extra benefitsNoneDental, vision, hearing (many plans)
Prior authorizationRareCommon for procedures, specialists, equipment

Who Medicare Advantage Serves Best

Who Original Medicare Serves Best

The switching trap: Switching from Medicare Advantage back to Original Medicare with Medigap is more difficult than the initial enrollment. In most states, Medigap insurers can charge higher premiums or deny coverage based on health status during open enrollment outside the initial 6-month Medigap enrollment window (the 6 months after you first enroll in Part B). If you start in Medicare Advantage and later develop a serious condition, you may find Medigap unaffordable or unavailable when you try to switch.

Medicare Advantage Enrollment in 2026

Medicare Advantage enrollment has grown significantly. More than half of all Medicare beneficiaries are now enrolled in Medicare Advantage plans. This growth has been driven by the $0 premium plans and extra benefits, but it has also led to increased scrutiny of prior authorization denials and network adequacy issues.

Before choosing a Medicare Advantage plan, review: the plan's provider directory to confirm your doctors are in-network, the drug formulary to confirm your medications are covered at reasonable tiers, the prior authorization requirements for any procedures you anticipate, and the plan's star rating at Medicare.gov.

Calculate Your Original Medicare Cost

See your total monthly cost for Original Medicare including IRMAA if applicable.

Open Calculator →

Related Guides