Plan A vs Plan B: The Coverage Floor Compared
Plans A and B are the two thinnest standardized Medigap designs. A is the mandatory baseline every carrier must offer; B adds skilled-nursing coinsurance and the Part B deductible on top. Both are rarely the right answer — but knowing exactly what they leave uncovered explains why G and N dominate the market.
| Benefit | Plan A | Plan B |
|---|---|---|
| Part A hospital coinsurance (days 61+) | 100% | 100% |
| Part A hospice / blood / home care | 100% | 100% |
| Skilled nursing facility coinsurance | Not covered | 100% |
| Part A deductible | Not covered | Not covered |
| Part B coinsurance (the 20%) | Not covered | Not covered |
| Part B deductible ($257) | Not covered | Covered |
What the uncovered 20% really costs
Both plans leave you paying 20% of every Part B-approved bill with no annual cap — chemotherapy, infusion drugs, outpatient surgery all flow through Part B. One cancer-treatment year can produce five-figure coinsurance. Plan A also leaves the $1,676 Part A hospital deductible uncovered. That is the structural reason A and B sit at the bottom of the value table despite low premiums: you retained the exact tail risk Medigap exists to remove.
When A or B still makes sense
There are two narrow cases. First, guaranteed-issue buyers with serious health conditions who can only qualify for A or B in their state’s GI menu — partial protection beats none. Second, rare situations where a carrier’s A/B pricing is disproportionately cheap in a given county. Outside those cases, the premium jump from B to G is typically modest and buys the Part B coinsurance — the single largest uncovered exposure on A and B.
FAQ
Why must every carrier sell Plan A?
Federal rules require carriers offering any Medigap plan to offer A (and C or F for pre-2020 eligibles), guaranteeing a baseline product exists.
Is Plan B the same as Part B of Medicare?
No — Medicare Part B is outpatient medical coverage itself; Medigap Plan B is a supplement design that happens to share the letter.
Can I upgrade from A to G later?
Yes, with underwriting in most states. Plan A holders are typically healthy enough to pass, since A attracts few high-claim members.
Related reading: Plan A full file · Plan G full file · All Medigap plans · Guaranteed-issue rights