Turning 65 (or otherwise becoming Medicare-eligible) brings a decision that trips up even financially savvy people: should you choose Medicare Advantage or a Medicare Supplement (Medigap) plan? Both build on Original Medicare, but they work in very different ways — and picking the wrong one can be costly or hard to reverse.
QUICK REFRESHER: WHAT ORIGINAL MEDICARE COVERS
Original Medicare has two parts:
Part A — hospital insurance (inpatient stays, skilled nursing, hospice)
Part B — medical insurance (doctor visits, outpatient care, preventive services)
Original Medicare alone typically covers about 80% of Part B costs, leaving a 20% gap — which is exactly where Medicare Advantage and Medigap come in, just from opposite directions.
WHAT IS MEDICARE ADVANTAGE (PART C)?
Medicare Advantage plans are offered by private insurers approved by Medicare. Instead of using Original Medicare directly, you get your Part A and Part B benefits (and usually Part D drug coverage) bundled through a private plan.
Pros:
- Often comes with a $0 premium in many areas
- Usually includes extra benefits: dental, vision, hearing, sometimes gym memberships
- Built-in annual out-of-pocket maximum
Cons:
- Typically uses HMO or PPO networks, so provider choice is more limited
- Requires referrals for specialists in many plans
- Coverage rules and costs vary significantly by plan and region
WHAT IS MEDICARE SUPPLEMENT (MEDIGAP)?
Medigap plans are also sold by private insurers, but they work alongside Original Medicare rather than replacing it. They help cover the “gaps” — deductibles, copays, and coinsurance that Original Medicare doesn’t pay.
Pros:
- Freedom to see any doctor who accepts Medicare, nationwide
- No referrals needed
- Predictable out-of-pocket costs
Cons:
- Higher monthly premiums than most Medicare Advantage plans
- Does not include drug coverage — you’ll need a separate Part D plan
- No extra benefits like dental or vision built in
SIDE-BY-SIDE COMPARISON
Monthly premium:
- Medicare Advantage: Often lower, sometimes $0
- Medicare Supplement: Generally higher
Provider network:
- Medicare Advantage: Limited (HMO/PPO)
- Medicare Supplement: Any provider accepting Medicare
Extra benefits:
- Medicare Advantage: Often included
- Medicare Supplement: Not included
Drug coverage:
- Medicare Advantage: Usually bundled
- Medicare Supplement: Separate Part D needed
Out-of-pocket costs:
- Medicare Advantage: Capped annually
- Medicare Supplement: Predictable but ongoing premium
Referrals needed:
- Medicare Advantage: Often, for specialists
- Medicare Supplement: No
WHICH ONE SHOULD YOU CHOOSE?
Consider Medicare Advantage if:
- You want lower monthly costs and are comfortable with a network of doctors
- You’d like dental, vision, or hearing benefits bundled in
- You don’t travel frequently or need out-of-state care
Consider Medicare Supplement if:
- You want maximum flexibility to see any Medicare-accepting doctor
- You travel often or split time between multiple states
- You prefer predictable costs over network restrictions
ENROLLMENT TIMING MATTERS
Your Medigap open enrollment period — the 6 months after you turn 65 and enroll in Part B — is the best time to buy a policy, since insurers can’t deny coverage or charge more based on health during that window. Miss it, and you may face medical underwriting later. Medicare Advantage, by contrast, has annual enrollment windows each fall, making it easier to switch plans year to year.
FINAL THOUGHTS
There’s no universally “better” option — it depends on how you value flexibility versus lower fixed costs, and how much you expect to use out-of-network or specialist care. Many people compare quotes from both categories side by side before deciding, since exact costs vary heavily by state and provider.
This article is for general informational purposes only and does not constitute medical or financial advice. Consult a licensed Medicare advisor for guidance specific to your situation.