Medicare Advantage vs Medigap: The 10-Year Cost Math

Medicare Advantage and Medigap answer the same question — "who pays the 20% Original Medicare doesn't?" — in opposite ways. Medicare Advantage replaces Original Medicare with a private plan that usually has a low or $0 premium, a network and a yearly out-of-pocket cap. Medigap keeps Original Medicare and adds a policy you pay for every month, in exchange for very few bills when you're sick.

Both paths start with the same Part B premium, $202.90 a month in 2026 (CMS). What differs is everything after that.

Medicare Advantage or Medigap? Decide in This Order

Answer four questions in this order and most people have their answer. The order matters because the first question can take one option off the table for good, while the last one — price — is the one people usually start with.

1. Are you inside your Medigap open enrollment period? For six months after you're 65 and in Part B, any Medigap insurer must sell you a policy without health questions. After that, most states allow underwriting. Check your dates on the Medigap open enrollment calculator.
2. Do you need specific doctors, or travel a lot? Medicare Advantage networks are usually local. Original Medicare with Medigap works with any provider in the country that takes Medicare.
3. Could you handle a worst-case year? Medicare Advantage limits your in-network costs, but the federal ceiling for 2026 is $9,250, and $13,900 for in- and out-of-network care combined (KFF).
4. Only then: compare premiums. Medigap premiums vary by state, age and insurer; get real quotes.

The 10-year cost math

To compare a decade, we priced three scenarios. The official figures are 2026's; two inputs are assumptions you should replace with your own quotes: a Plan G premium of $200 a month and $1,000 a year of Medicare Advantage copays in a healthy year.

The Medigap column barely moves: Plan G pays everything after the Part B deductible, $283 in 2026. The Medicare Advantage column depends almost entirely on your health. Part B premiums are the same on both sides and left out; add a standalone Part D premium to the Medigap side.

Is Medigap Worth It? When the Premium Pays for Itself

Medigap is worth it when you'd otherwise reach your Medicare Advantage plan's out-of-pocket cap more than about once or twice in ten years — or when freedom to see any doctor matters to you. At the assumptions above, two bad years in a decade roughly break even, and every bad year after that makes Medigap the cheaper path.

The odds of bad years rise with age. A diagnosis that needs a specialist, surgery or months of treatment can reach the cap in one year, and serious conditions tend to come back. That's why our break-even point is lower for people in their late 70s and 80s than for a healthy 65-year-old.

There is a middle ground. Medigap Plans K and L cost less and have their own out-of-pocket limits — $8,000 and $4,000 for 2026 (CMS) — while keeping the any-doctor freedom of Original Medicare.

What does each path cover that the other doesn't?

The two paths cover the same Medicare services, but they wrap them in very different rules. The differences that matter most show up when you need care, not when you enroll, so read them as "what happens on a bad day."

Medicare Advantage usually adds: routine dental, vision and hearing allowances, gym memberships and drug coverage in one card. It usually requires: staying in a network, referrals for specialists in many HMOs, and prior authorization for many services, from MRIs to skilled nursing stays — a step Original Medicare rarely uses (KFF: Medicare Advantage in 2026).

Medigap adds: freedom to see any provider nationwide that accepts Medicare, no referrals, no plan-level prior authorization, and — in most plans — 80% coverage of emergency care abroad up to the policy's limits. It doesn't include: drug coverage (you add Part D) or routine dental and vision.

How Medigap premiums change as you age

Medigap insurers price policies in one of three ways, and the method matters more than the starting price (CMS: Choosing a Medigap Policy):

• Community-rated: everyone pays the same, regardless of age.
• Issue-age-rated: the price is set by your age when you buy and doesn't rise because you get older.
• Attained-age-rated: cheapest at 65, then rises every year as you age.

All three also rise with inflation and claims. When comparing quotes, ask which method the insurer uses; a cheap attained-age policy at 65 can be the expensive one by 80.

The guaranteed-issue trap

The most expensive mistake isn't picking the "wrong" plan in year one. It's starting with Medicare Advantage, getting sick, and then finding you can't buy Medigap. Outside your six-month window and a few special situations, insurers in most states can charge more or refuse you because of your health (CMS: Choosing a Medigap Policy).

Who should choose which

The right answer depends less on the plans than on your health, your budget and where you spend the year. Here's how we'd sort the most common situations.

If money is tight, check whether a Medicare Savings Program covers you before choosing either.

Our take

For most people who can afford it at 65, we'd choose Original Medicare with Medigap during the six-month window. It costs more in good years and much less in bad ones, and it keeps your options open in a way Medicare Advantage can't undo.

If the premium would strain your budget, a Medicare Advantage plan with a low out-of-pocket limit and your doctors in its network is a sensible choice — just know it's a hard one to reverse.

Before you decide, price both paths on the Medicare premium calculator, and if your income is high, check whether IRMAA adds to the Part B premium on either side.