Dorothy Chen
Your neighbor paid almost nothing out of pocket after her knee replacement. Your cousin paid thousands for the exact same surgery. Both have Medicare. Same program, wildly different bills.
The difference usually comes down to one thing: your neighbor had a Medigap plan. Your cousin didn’t.
What Medigap Actually Is (And What People Get Wrong About It)
Most people think Medicare covers “most” of their healthcare costs. I’ll be blunt: that belief costs seniors real money every year.
Original Medicare, which is Part A (hospital insurance) and Part B (medical insurance), leaves significant gaps. Deductibles. Copayments. Coinsurance. And here’s the part that genuinely surprises people: no out-of-pocket maximum at all. You could theoretically keep paying forever.
Medigap, also called Medicare Supplement Insurance, is private health insurance designed to fill exactly those gaps. You pay a monthly premium to a private insurance company. They pay what Original Medicare won’t. The name is literal. It supplements Medicare. Doesn’t replace it.
When I first started helping people with this, I was struck by how standardized these plans actually are. The federal government, through the Centers for Medicare & Medicaid Services, defines exactly what each plan type must cover. A Plan G from Humana covers the same benefits as a Plan G from Blue Cross Blue Shield. The only differences between carriers are price and customer service.
One critical thing upfront: Medigap only works with Original Medicare. If you’re enrolled in Medicare Advantage (Part C), you can’t use a Medigap plan. These are two completely different paths.
The Standardized Plan Letters: What Each Plan Covers
Ten standardized Medigap plan types exist in most states, labeled A through N. A few things before we go through them.
Plans C and F are no longer available to anyone who became eligible for Medicare on or after January 1, 2020. If you enrolled before that date, you can keep yours. New enrollees can’t sign up anymore because Congress decided to phase out the Part B deductible coverage for incoming beneficiaries.
Here’s what the most popular plans actually cover:
| Benefit | Plan A | Plan G | Plan K | Plan N |
|---|---|---|---|---|
| Part A coinsurance & hospital costs | Yes | Yes | Yes | Yes |
| Part B coinsurance/copayment | Yes | Yes | 50% | Yes (copays apply) |
| Blood (first 3 pints) | Yes | Yes | 50% | Yes |
| Part A hospice coinsurance | Yes | Yes | 50% | Yes |
| Skilled nursing facility coinsurance | No | Yes | 50% | Yes |
| Part A deductible | No | Yes | 50% | Yes |
| Part B deductible | No | No | No | No |
| Part B excess charges | No | Yes | No | No |
| Foreign travel emergency | No | Yes (80%) | No | Yes (80%) |
| Out-of-pocket limit (2024) | None | None | ~$7,060 | None |
Plan G dominates the market for new enrollees right now. Compared to the old Plan F, it doesn’t cover the Part B deductible, which is $240 per year in 2024. You pay that once and Plan G covers everything else. For most people, the premium savings versus Plan F exceed that $240 anyway.
Plan N deserves a hard look if you’re relatively healthy and want lower monthly costs. You’ll pay small copays ($20 for office visits, up to $50 for emergency room visits that don’t lead to hospital admission), and you’re exposed to Part B excess charges. These are the extra amounts doctors who don’t accept Medicare assignment can legally charge. Not every doctor does this, but it’s a real exposure in certain specialties and markets.
When You Can (And Can’t) Enroll Without Medical Underwriting
Best Medicare Supplement Plans - What’s Changed for 2026 · Medicare Specialist - Abt Insurance Agency on YouTube
This is where people make expensive, permanent mistakes.
Your golden window is the Medigap Open Enrollment Period. It starts the month you turn 65 AND enroll in Medicare Part B, and it runs for six months. During this window, insurance companies cannot deny you, charge you more for health conditions, or impose waiting periods. They have to accept you.
Outside that window, most states allow medical underwriting. Insurers can examine your health history, charge higher premiums, reject you entirely, or impose waiting periods for pre-existing conditions. If you have diabetes, heart disease, or cancer history, getting a Medigap plan becomes very difficult and very expensive outside open enrollment.
Some Protected Enrollment Rights kick in under specific circumstances: losing employer coverage, your Medicare Advantage plan leaving your area, or moving. Medicare.gov lists exactly which situations qualify. Check it if you’re considering a switch.
New York, Massachusetts, and Connecticut have their own continuous open enrollment rules that favor consumers. If you live there, the rules are different. But don’t assume anything, verify.
How Medigap Pricing Works (And Why the Same Plan Varies So Much)
Get quotes for Plan G from three companies and you’ll see $90 to $250 per month. That range is real.
How’s that possible if benefits are identical?
The answer is pricing structure. There are three methods:
Community-rated: Everyone pays the same premium regardless of age. Rates can increase over time, but your age doesn’t raise them individually. Generally better if you’re older.
Issue-age-rated: Your premium depends on your age when you bought the policy. Younger buyers lock in lower rates. Rates increase, but not because you aged.
Attained-age-rated: Your premium goes up as you age. Cheap at 65, potentially expensive at 75. This is the most common model and the one that shocks people in their late 70s.
Which pricing method a company uses matters for your long-term costs. An attained-age plan looks cheap initially and becomes expensive over time. I’ve watched clients surprised by rate increases in their late 70s because they never asked this question.
Companies also differ on loss ratios, administrative costs, and claims histories. Looking at a company’s rate increases over the past five years is something brokers can pull for you.
A Step-by-Step Guide to Choosing and Enrolling in a Medigap Plan
Approaching 65 or currently in your open enrollment window? Here’s the practical approach:
Confirm your Medicare Part B start date. Your Medigap open enrollment begins the month Part B takes effect, not necessarily your birthday month. These can differ.
Decide: Medigap or Medicare Advantage. These are fundamentally different. Medigap gives you maximum provider flexibility nationwide and predictable costs. Medicare Advantage has lower premiums but network restrictions and variable out-of-pocket expenses. Neither is universally right.
Pick your plan letter. For most healthy people today, Plan G or Plan N make sense. Plan G offers near-comprehensive coverage. Plan N saves money if you’re comfortable with small copays and potential excess charges.
Get quotes from multiple carriers. Use a licensed broker who works with multiple companies, not a captive agent selling just one company. Premiums vary significantly. A broker shows you rate increase histories.
Ask the pricing model directly. “Is this community-rated, issue-age-rated, or attained-age-rated?” Write the answer down.
Check financial strength ratings. Look up the insurer on AM Best or Moody’s. You want a company that’ll be around and solvent for decades.
Apply and confirm your effective date. Make sure Medigap coverage starts on the same date as Part B, or very soon after. Don’t leave a gap.
Don’t forget Part D. Medigap plans don’t cover prescription drugs. You’ll need a separate Part D plan for medications.
Medigap isn’t right for everyone, and the right plan letter isn’t the same for every person. But understanding what these plans do, how they’re priced, and when you can enroll without medical scrutiny is genuinely valuable knowledge before you need it. The best time to decide is before something goes wrong, not after.
If you’re approaching 65 or helping family think through this, talk with a licensed independent Medicare broker and cross-reference their guidance with Medicare.gov. That’s the most practical next step.
This article is for informational purposes only. Medicare rules change annually. Always verify current plan details at Medicare.gov or by calling 1-800-MEDICARE (1-800-633-4227). This site does not sell insurance or recommend specific plans.
Sources & References
- Medicare.gov, What’s Medicare Supplement Insurance (Medigap)?, Official overview of Medigap plans, coverage, and enrollment rules
- CMS.gov, Choosing a Medigap Policy Guide, Federal guidance on standardized plan benefits and rights
Recommended Resources
Disclosure: As an Amazon Associate, we earn a small commission from qualifying purchases at no extra cost to you. We only recommend products that genuinely support the topics covered in this article.
- Medicare For Dummies (~$22), The definitive consumer guide to Medicare, enrollment windows, Part A/B/C/D, and supplement plans.
- Get What’s Yours for Medicare (~$17), Maximize your Medicare benefits and minimize out-of-pocket costs. Covers Part D drug coverage gaps and Medigap in depth.
- Get What’s Yours for Medicare (Original) (~$15), The original bestselling guide to navigating Medicare and Social Security timing, over 100,000 copies sold.
