Original Medicare is excellent coverage with a catch: it wasn't designed to pay 100% of your bills. Between deductibles, coinsurance, and copays, it leaves gaps — and, crucially, no annual limit on what those gaps can add up to. Medigap (also called Medicare Supplement insurance) exists to fill them. It's a private policy that sits alongside Original Medicare and picks up much of what Medicare leaves for you to pay.
The result, for many people, is the most predictable version of Medicare there is: you pay a known monthly premium, and surprise medical bills mostly disappear.
Medigap plans are standardized by the federal government and sold by letter: Plan G, Plan N, and so on. Here's the part that makes shopping refreshingly simple: a Plan G from one insurance company covers exactly the same benefits as a Plan G from any other. In most states the benefits are identical by law. What differs is the price, the company's rate-increase history, and the service — which means the smart way to shop is to pick your letter first, then find the carrier offering it at the best value. That's precisely the comparison an independent agency runs for you.
One important note on timing: when you first enroll in Part B, you typically get a one-time Medigap open enrollment window during which insurers generally can't deny you coverage or charge more based on your health. Outside that window, medical underwriting often applies in many states — so the decision deserves attention early. Our Medicare guide library covers the details.
Notice that last row: Medigap does not cover prescriptions. The classic package is three pieces — Original Medicare, a Medigap policy, and a stand-alone Part D drug plan. For 2026, Part D out-of-pocket costs for covered drugs are capped at $2,100 for the year, which makes the drug side of the equation far more predictable than it used to be.
One rule surprises people: Medigap pairs only with Original Medicare. You cannot use a Medigap policy with a Medicare Advantage plan — it's one path or the other. Broadly, Medigap suits people who want maximum provider freedom (any Medicare doctor in the country, no referrals), travel frequently, or simply want their health costs to be boring and predictable — and who are comfortable paying a higher fixed premium for it. Medicare Advantage suits people who prefer low monthly premiums and bundled extras and are comfortable with a network. We put the two side by side on our Medicare page.
A few practical notes before you shop. Since benefits within a letter are identical, carriers compete on price and on how they raise rates over time — two policies identical today can drift apart over the years, so a carrier's rate history matters as much as its opening quote. Premiums also vary by how they're structured and by where you live, and some states add their own consumer-friendly rules about when you can switch plans without health questions. None of this changes what the plan covers; it changes what you'll pay for it over a decade — which is exactly the long view worth taking, since many people keep a Medigap policy for the rest of their lives.
Travelers, take note: because Medigap rides on Original Medicare, your coverage works with any provider in the country that accepts Medicare — no networks, no referrals, no "is this hospital in-network" phone calls from a vacation. For people who split time between states or drive to see grandkids, that nationwide freedom is often the deciding factor all by itself. Have a life event coming up, like retiring or losing employer coverage? Those transitions often open special enrollment windows — timing them well protects your options.
Because Medigap benefits are standardized, the only way to overpay is to pick the wrong carrier for your letter — and the only way to know is to compare. We do that across the carriers we represent, free. Call 561-339-0727 or browse common questions to get oriented first.
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