A Medicare Supplement policy — usually called Medigap — does not replace Original Medicare. It sits alongside it and pays the share Medicare leaves to you: the deductibles, the copays, and the 20% coinsurance that otherwise has no ceiling.
How it works day to day
You show your Medicare card and your Medigap card. Medicare pays its part, the policy pays its part, and in most cases nothing is left for you. There is no network: any provider in the country who accepts Medicare accepts your plan. No referrals, and no prior authorization from the insurer.
Plans are standardised
This is the part people find surprising. Medigap plans are lettered — A, B, D, G, K, L, M, N, and F for those eligible before 2020 — and the benefits of each letter are fixed by law. Plan G from one carrier covers exactly what Plan G from another carrier covers.
What differs between carriers is the premium, how sharply they raise it over time, and the quality of their service. That is a genuinely useful thing to know, because it means shopping Medigap is mostly about price and the carrier’s rate history — not about deciphering benefit tables.
The two most common choices
| Plan G | Plan N | |
|---|---|---|
| Part A deductible | Covered | Covered |
| Part B deductible | You pay it | You pay it |
| Part B coinsurance | Covered | Covered, with small copays |
| Office visit copay | None | Up to $20 |
| Emergency room copay | None | Up to $50 (waived if admitted) |
| Monthly premium | Higher | Lower |
Plan N costs less each month and asks for small copays when you use care. Whether that is a better deal depends on how often you see a doctor. We can run the numbers for your situation.
Timing is the thing to get right
When you first enrol in Part B at 65 you get a six-month Medigap Open Enrollment Period. During it you can buy any Medigap policy sold in your state at the standard price, regardless of your health history. No questions, no underwriting, no declines.
Once that window closes, most states allow insurers to underwrite. They can raise your price or turn you down because of your medical history. A few states have more generous rules; most do not.
This is the reason a lot of people who would prefer a Medigap plan end up unable to get one. If you are approaching 65, it is worth deciding on purpose rather than by default.
What Medigap does not cover
Prescription drugs. You add those separately with a Part D plan. Medigap also does not cover routine dental, vision, or hearing, which some Advantage plans do.
Compare Medigap rates
Because the benefits are standardised, comparing Medigap is mostly about finding a well-priced carrier with a stable rate history. We will do that for you.