One of the most confusing parts of shopping for Medicare Supplement insurance is the alphabet soup of plan letters: A, B, D, G, K, L, M, N — and the now-closed C and F. Unlike Medicare Advantage, where every insurer designs its own benefit package, Medigap plans are standardized by federal law. This article breaks down exactly what each letter covers so you can compare apples to apples.
Why Medigap Plans Use Letters, Not Brand Names
The National Association of Insurance Commissioners (NAIC), working with federal Medicare rules, created a standardized set of Medigap benefit packages decades ago specifically to stop confusing marketing practices. Before standardization, insurers could name plans almost anything and stuff them with different combinations of benefits, making comparison nearly impossible. Today, a Plan G sold by one national carrier must cover the same core benefits as a Plan G sold by a regional carrier. This is what makes Medigap shopping fundamentally a price and service comparison, not a benefits comparison, once you’ve picked your letter.
The Full Medigap Comparison Chart
| Benefit | A | B | D | G | K | L | M | N |
|---|---|---|---|---|---|---|---|---|
| Part A coinsurance/hospital costs | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ |
| Part B coinsurance/copayment | ✓ | ✓ | ✓ | ✓ | 50% | 75% | ✓ | ✓ (with small copays) |
| Blood (first 3 pints) | ✓ | ✓ | ✓ | ✓ | 50% | 75% | ✓ | ✓ |
| Part A hospice coinsurance | ✓ | ✓ | ✓ | ✓ | 50% | 75% | ✓ | ✓ |
| Skilled nursing facility coinsurance | — | — | ✓ | ✓ | 50% | 75% | ✓ | ✓ |
| Part A deductible | — | ✓ | ✓ | ✓ | 50% | 75% | 50% | ✓ |
| Part B deductible | — | — | — | — | — | — | — | — |
| Part B excess charges | — | — | — | ✓ | — | — | — | — |
| Foreign travel emergency | — | — | 80% | 80% | — | — | 80% | 80% |
Note: Plans C and F are only available to people who were eligible for Medicare before January 1, 2020. If you became eligible on or after that date, Plan G is the most comprehensive option you can buy new.
Plan G: The Most Popular Choice for New Enrollees
Since Plan F closed to new beneficiaries, Plan G has become the default “comprehensive” choice. It covers everything except the annual Part B deductible, which is a relatively modest amount you pay once per year before Medigap coverage on Part B services kicks in. After that, Plan G holders typically pay $0 out of pocket for Medicare-covered services nationwide. For the full head-to-head against its closest competitor, read Plan G vs. Plan N: Which Saves You More Money?
Plan N: The Budget-Friendly Alternative
Plan N covers nearly as much as Plan G but trades a lower monthly premium for small copays — typically up to $20 for a doctor visit and up to $50 for an emergency room visit that doesn’t result in admission. Plan N also doesn’t cover Part B excess charges, which matters only if your doctor doesn’t accept Medicare assignment. For frequent travelers or those in states where excess charges are legally prohibited, Plan N is often the smarter financial choice.
Plan A: The Bare-Bones Option
Plan A is the most basic standardized Medigap plan, covering only the core benefits: Part A coinsurance and hospital costs, Part B coinsurance, the first three pints of blood, and Part A hospice coinsurance. It doesn’t touch either deductible. It’s the lowest-premium option but leaves you exposed to both the Part A and Part B deductibles every year.
Plans K and L: Cost-Sharing With a Safety Net
Plans K and L work differently from the others — instead of covering 100% of specific benefits, they cover a percentage (50% for K, 75% for L) of most cost-sharing, but they cap your total annual out-of-pocket spending. Once you hit the annual limit, the plan pays 100% of covered services for the rest of the year. These plans suit people comfortable with some financial risk in exchange for a lower premium and a hard ceiling on worst-case costs.
Plans B, D, and M: The Middle Tier
These plans sit between the bare-bones Plan A and the comprehensive Plan G, each covering a slightly different combination of the Part A deductible, skilled nursing coinsurance, and foreign travel emergency care. They’re less commonly sold today because Plan G and Plan N have captured most of the market, but they remain available in most states and can occasionally offer a good value depending on your insurer.
How to Actually Compare Plans in Your State
Because benefits are standardized, your real decision comes down to three things: which letter fits your health and travel habits, which insurer offers the best price for that letter in your zip code, and the insurer’s financial strength and customer service reputation. Premiums for identical Plan G coverage can vary by more than $100 a month between carriers in the same county — which is why comparing quotes matters even after you’ve settled on a letter.
See Plan G, Plan N, and other Medigap rates side by side in your area.
When You Can Buy Any Letter Without Medical Questions
Your ability to buy any of these plans without answering health questions depends on timing. During your one-time 6-month Medigap Open Enrollment Period, insurers must sell you any plan they offer at their best rate. Outside that window, you may face medical underwriting unless you qualify for a Guaranteed Issue Right. Learn more in Medigap Open Enrollment Period: Dates, Rules & What Happens If You Miss It and Guaranteed Issue Rights for Medigap.
Frequently Asked Questions
- Is Plan G the same no matter which company sells it?
- Yes — the core benefits of Plan G are federally standardized. The only differences between carriers are price, discounts, and customer service.
- Can I switch from Plan F to Plan G?
- Yes, existing Plan F holders can switch to Plan G, though outside your initial enrollment window you may need to pass medical underwriting. See our guide on switching Medigap plans.
- Why isn’t Plan F available anymore?
- Federal law closed Plans C and F to anyone who became newly eligible for Medicare on or after January 1, 2020, because they cover the Part B deductible, which lawmakers wanted to phase out to encourage some cost-sharing.
