Medicare uses letters twice, for two completely different things, and mixing them up is probably the single most common Medicare confusion there is.

Medicare Parts, A, B, C, and D, describe the actual pieces of your coverage. Part A is hospital care. Part B is doctor visits and outpatient care. Part C is Medicare Advantage, a private-plan alternative way to get your A and B (often bundled with D) through an insurance company instead of the government directly. Part D is prescription drug coverage.

Medigap Plans use an entirely different, unrelated lettering system, A, B, D, G, K, L, M, N, and a couple of others, for a completely different kind of product: supplemental insurance that only works alongside Original Medicare, helping cover the deductibles and coinsurance that Parts A and B leave you owing.

Here's the trip-up that catches almost everyone at some point: Medigap Plan D has nothing to do with drug coverage. It doesn't pay for a single prescription, that's still Part D's job, entirely separate. Same letter, two unrelated products.

One more thing worth knowing: every insurance company's Medigap Plan G has to offer the exact same standardized core benefits as every other company's Plan G, by law. The letter defines the coverage itself, only the price and the company behind it differ, which makes comparing Medigap genuinely simpler than comparing Medicare Advantage plans.

Which letter has confused you the most, a Part or a Medigap Plan? Tell us in the comments, you're definitely not the only one.

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