Medicare Medigap plans: what they cover, what they cost, and how to choose

On the hospital side, the Part A inpatient deductible is $1,736 per benefit period, not per year. A second hospitalization in the same calendar year can trigger a second $1,736 charge if a new benefit period has begun. For days 61 to 90, you owe $434 per day in coinsurance. Beyond day 90, you draw from a pool of 60 lifetime reserve days at $868 per day, and after those are gone, you pay the full cost.

Medigap policies attach to Original Medicare and pick up some or all of those leftover amounts, depending on the plan letter you choose.

In short: Original Medicare's cost-sharing has no ceiling, and Medigap exists specifically to fill that ceiling gap.

Federal law requires that every Medigap plan with the same letter deliver the same core benefits, regardless of which private insurer sells it. That makes comparing plans straightforward: you are comparing price and company service quality, not hidden benefit differences.

Plans available to people turning 65 today

Plans C and F are only available to people who were eligible for Medicare before January 1, 2020. If you turned 65 after that date, the relevant comparison set is Plans A, B, D, G, K, L, M, and N, plus the high-deductible version of Plan G.

A few details worth unpacking:

Plan G is the most comprehensive option for new enrollees. It covers everything Plan F covered except the Part B deductible of $283, and it pays excess charges (the up-to-15% above the Medicare-approved amount that non-participating providers may bill).

High-deductible Plan G works like standard Plan G but you pay all costs up to the 2026 high-deductible threshold of $2,950 before the plan begins paying. In exchange, the monthly premium is substantially lower, making it appealing if you are generally healthy and want a cap on catastrophic exposure.

Plans K and L have lower premiums because they only cover a share (50% and 75%, respectively) of most cost-sharing. They also have their own annual out-of-pocket limits, which CMS adjusts periodically.

Plan N covers the Part A deductible and most of Part B coinsurance, but small copays may apply for some office visits and emergency room visits that do not result in an inpatient admission. It does not cover excess charges.

In short: Plan G and high-deductible Plan G are the two plans worth understanding deeply for most new enrollees; every other letter trades some coverage for a lower premium.

No Medigap plan covers Part D prescription drug benefits. Part D (the prescription drug benefit) is a separate enrollment you make through a standalone plan or, if you choose Medicare Advantage (Part C, the all-in-one private alternative to Original Medicare), it is often bundled in. You cannot hold a Medigap policy and a Medicare Advantage plan at the same time; Medigap only works alongside Original Medicare Parts A and B.

Medigap also does not cover dental, vision, hearing aids, or long-term custodial care. Those require separate coverage or come as extras in some Medicare Advantage plans.

In short: Medigap is a cost-sharing supplement for Original Medicare, not a replacement for Part D or dental and vision coverage.

The one guaranteed-issue Medigap window is 6 months, starting the month you are both 65 and enrolled in Part B. During this window, an insurer cannot refuse to sell you any plan it offers, cannot charge you more because of health conditions, and cannot make you wait for coverage of pre-existing conditions. That protection disappears once the window closes.

Outside that window, most states allow insurers to use medical underwriting, meaning they can decline you, charge higher premiums, or exclude coverage for pre-existing conditions. There are exceptions:

• Year-round guaranteed issue states: Some states, including New York and Connecticut, require insurers to sell Medigap to any Medicare beneficiary at any time, regardless of health.
• Plan-to-plan switching: Washington allows guaranteed-issue switching between Medigap plans under certain conditions.
• Birthday-rule states: California, Oregon, and a growing number of others (roughly 16 states with widely varying windows, including New Mexico effective January 2027) allow you to switch Medigap plans around your birthday each year without underwriting, though the rules differ significantly by state.

Beyond the open enrollment window, there are federally guaranteed special enrollment rights in specific situations: your Medigap insurer goes bankrupt, you move out of a plan's service area, or you leave a Medicare Advantage plan under qualifying circumstances, among others.

In short: Enroll during the 6-month guaranteed-issue window if at all possible; the special protections outside that window are narrower than most people expect.

Insurers use three pricing methods, and the method matters as much as the starting premium.

Community-rated (no-age-rated): Everyone in the plan pays the same premium regardless of age. Premiums may rise over time due to inflation but not because you get older.

Issue-age-rated: Your premium is set based on your age when you buy the policy and stays flat relative to that starting point. Younger buyers lock in a lower base.

Attained-age-rated: Your premium starts low but increases as you age. These plans often look cheapest at 65 but can become the most expensive by your 70s and 80s.

Beyond the pricing method, insurers compete on the same benefit package, so the same Plan G letter can vary by hundreds of dollars annually between companies in the same zip code. That variation is real and worth comparing.

Premiums you pay for Medigap are separate from and in addition to the Part B premium. If your income in 2024 exceeded $109,000 (single) or $218,000 (joint), you also pay an income-related adjustment known as IRMAA (Income-Related Monthly Adjustment Amount) on top of the standard Part B premium, and IRMAA tiers continue upward from there.

In short: An attained-age plan can look attractive at 65 and become expensive by 75; ask which pricing method applies before you buy.

Medicare Advantage (Part C) and Medigap serve different philosophies. Advantage plans replace Original Medicare with a private plan that typically bundles drug coverage and sometimes dental and vision, often at a $0 monthly premium on top of Part B. Medigap keeps you in Original Medicare and supplements it.

The practical differences:

• Provider networks: Original Medicare with Medigap lets you see any provider in the country who accepts Medicare, with no referrals required. Advantage plans usually have network restrictions and may require prior authorization for certain services. In 2026, standard prior-authorization decisions in Medicare Advantage must come within 7 calendar days; expedited decisions must come within 72 hours under CMS-0057-F.
• Predictability vs. premium: Medigap trades a higher monthly premium for very predictable out-of-pocket costs. Advantage trades a lower (sometimes $0) premium for variable cost-sharing up to the plan's maximum out-of-pocket limit. In 2026, the federal in-network cap for Medicare Advantage is $9,250, though enrollment-weighted average in-network limits run closer to $5,421 according to KFF.
• Drug coverage: With Medigap, you enroll in a standalone Part D plan separately. With Advantage, it is usually included.

Neither path is universally better. The right answer depends on your health usage, where you live, your provider relationships, and how you weigh premium certainty against flexibility.

To find out more about coverage, please contact us to discuss plan options.

In short: Medigap fits people who want cost predictability and full provider access; Advantage fits people who want lower upfront premiums and are comfortable with network and authorization rules.

A practical sequence:

1. Confirm your enrollment window. Know whether you are in your 6-month guaranteed-issue period or need to assess your underwriting risk before applying.
2. Choose a letter first. Decide which benefit structure fits your health needs and risk tolerance before comparing prices. For most new enrollees, Plan G or high-deductible Plan G covers the comparison.
3. Compare premiums for the same letter across insurers. Benefits are identical; price and company reliability are not. Your state's Department of Insurance or the Medicare Plan Finder at medicare.gov can help.
4. Ask about the pricing method. Community-rated or issue-age-rated plans often cost more upfront but age more predictably.
5. Enroll in Part D separately. If you choose Medigap, do not wait to enroll in a standalone Part D drug plan. Going 63 or more days without creditable drug coverage after your Initial Enrollment Period triggers a permanent late-enrollment penalty equal to 1% of the national base beneficiary premium (which is $38.99 in 2026) for each full month without coverage.
6. Reassess during AEP if your situation changes. The Annual Enrollment Period (AEP) runs October 15 to December 7 each year for Part D plan changes. Medigap itself has no annual open enrollment, so switching later may require underwriting.

In short: Pick the letter, then shop the price, then nail down Part D before the penalty clock runs.