When Original Medicare Isn’t Enough
Medicare covers a lot — but not everything. According to the Kaiser Family Foundation, the average Medicare beneficiary spent $7,000 out of pocket on healthcare in a recent year, even with traditional Medicare coverage in place. Copays, coinsurance, and hospital deductibles can pile up fast, especially if you’re managing a chronic condition or recovering from a major procedure.
That’s exactly the gap Medicare Supplement Insurance — commonly called Medigap — is designed to fill. If you’re approaching 65, already enrolled in Medicare, or helping an aging parent navigate coverage options, this guide walks you through exactly how Medigap works, what it costs, and whether it makes sense for your situation.
By the end of this article, you’ll understand the different Medigap plan types, how to enroll without being denied coverage, what you’ll realistically pay in premiums, and the most costly mistakes people make when shopping for a supplement policy.
What Is Medicare Supplement Insurance (Medigap)?
Medicare Supplement Insurance — Medigap for short — is private health insurance that works alongside Original Medicare (Parts A and B). It does not replace Medicare. Instead, it picks up costs that Medicare leaves behind: deductibles, coinsurance, and copayments that would otherwise come out of your pocket.
According to the Centers for Medicare & Medicaid Services (CMS), more than 14 million Americans are currently enrolled in a Medigap plan. These policies are sold by private insurers, but they’re standardized by the federal government — meaning the benefits in a Plan G from one insurer are legally required to match the benefits in a Plan G from any other insurer.
That standardization is a big deal. You’re not comparing apples to oranges when you shop for Medigap. You’re comparing prices for the same basket of benefits.
Medigap policies only work with Original Medicare. If you’re enrolled in Medicare Advantage (Part C), you cannot use a Medigap plan. You have to choose one path or the other.
Key Benefits of Medigap Coverage
The most compelling reason to buy a Medigap plan is predictability. With the right policy, your out-of-pocket medical costs become largely fixed — which makes budgeting in retirement much easier.
Here’s a breakdown of costs Medigap plans can cover, depending on which plan type you choose:
- Medicare Part A deductible: $1,676 per benefit period in 2026 — most Medigap plans cover this in full
- Medicare Part B coinsurance: Typically 20% of all outpatient costs — covered by most plans
- Hospital coinsurance and extended hospital stays: Medicare only covers 60 reserve days; Medigap extends that coverage significantly
- Skilled nursing facility coinsurance: Partially or fully covered depending on your plan
- Foreign travel emergency coverage: Available on select plans, generally up to 80% of costs after a deductible
Consider this scenario: Sandra, 68, has a hip replacement surgery that requires four days in the hospital plus six weeks of physical therapy. With Original Medicare only, she could face $3,000–$5,000 in out-of-pocket costs. With a solid Medigap plan like Plan G, her out-of-pocket exposure drops to near zero after the Part B deductible.
That kind of protection matters — especially when healthcare costs are one of the top reasons Americans exhaust their retirement savings prematurely, according to the Employee Benefit Research Institute.
How to Choose the Right Medigap Plan
As of 2026, there are ten standardized Medigap plans available in most states: Plans A, B, D, G, G-HD (high-deductible), K, L, M, and N. (Plans C and F are no longer available to new Medicare enrollees who became eligible after January 1, 2020.)
The most popular plans for new enrollees today are Plan G and Plan N. Here’s a quick breakdown:
- Plan G: Covers nearly everything Medicare doesn’t — except the Part B deductible ($257 in 2026). Highest coverage, higher premiums.
- Plan N: Covers most costs but requires small copays (up to $20 for office visits, up to $50 for ER visits) and doesn’t cover Part B excess charges. Lower premiums than Plan G.
- Plan G High-Deductible: Same benefits as Plan G but requires you to meet a $2,870 deductible (2026 figure) before coverage kicks in. Much lower monthly premium — good for generally healthy enrollees.
- Plan K and Plan L: Cost-sharing plans with annual out-of-pocket limits. They pay a percentage (50% or 75%) of costs, so you share more risk in exchange for lower premiums.
Your best plan depends on your health history, how often you use medical services, and your comfort with financial risk. If you see multiple specialists regularly, Plan G’s comprehensive coverage often pays for itself. If you’re healthy and want to keep premiums low, Plan N or the high-deductible Plan G may be smarter choices.
To compare your retirement income options further, check out our guide on Social Security Optimization: Maximize Your Benefits — because your healthcare costs in retirement are directly tied to how much monthly income you’ll have from Social Security.
When and How to Enroll in Medigap
Timing your Medigap enrollment correctly can be the single most important financial decision you make around Medicare. Here’s why:
Federal law gives you a 6-month Medigap Open Enrollment Period that starts the month you turn 65 and are enrolled in Medicare Part B. During this window, insurers cannot deny you coverage, charge you higher premiums because of pre-existing conditions, or make you wait before coverage begins.
Once that window closes, you’re subject to medical underwriting in most states. That means insurers can review your health history, charge you significantly more, or flat-out reject your application if you have conditions like diabetes, heart disease, or a history of cancer.
Here’s a step-by-step enrollment process:
- Enroll in Medicare Parts A and B first. You must have Original Medicare before purchasing Medigap. Most people enroll at 65 unless they have employer coverage that qualifies as a delay exception.
- Note your Part B start date. Your 6-month open enrollment period begins on the first day of the month you have both Part B and are 65 or older.
- Compare plan types, not just insurers. Since benefits are standardized, compare Plan G vs. Plan N based on your expected healthcare usage — not just marketing materials.
- Get quotes from multiple insurers. Use Medicare’s official Plan Finder tool at medicare.gov or work with an independent Medicare broker. Premiums for the same plan can vary by 30–50% between insurers in the same zip code.
- Understand how premiums are calculated. Insurers use three pricing methods: community-rated (everyone pays the same), issue-age-rated (locked at your age when you enroll), and attained-age-rated (increases as you age). Attained-age plans often start cheapest but become the most expensive over time.
- Submit your application and confirm coverage start date. Keep copies of everything and set a reminder to review your plan annually during Medicare’s Open Enrollment Period (October 15 – December 7).
Costs, Fees, and What to Watch Out For
Medigap is not free. Premiums vary considerably based on your location, age, gender, tobacco use, and the plan you choose. According to AHIP (America’s Health Insurance Plans), the average monthly premium for a Medigap Plan G in 2026 ranges from roughly $120 to $250 per month for a 65-year-old non-smoker, depending on state and insurer.
Here’s a realistic cost picture for a 65-year-old enrolling in Plan G:
- Monthly premium: $150–$200 on average nationally
- Annual Part B deductible: $257 (you pay this out of pocket even with Plan G)
- Total estimated annual Medigap cost: $2,057–$2,657 per year
Additionally, remember that Medigap does not cover the following:
- Prescription drugs (you need a separate Part D plan for that)
- Vision, dental, or hearing coverage
- Long-term care
- Private-duty nursing
Budget accordingly. Many Medigap enrollees pair their policy with a standalone Part D prescription drug plan ($30–$80/month average) and a separate dental/vision plan or discount program.
If you’re weighing other insurance-backed financial tools, our breakdown of Whole Life Insurance as a Financial Asset: Is It Worth It? may give you additional context on how insurance products fit into a broader retirement plan.
Common Mistakes to Avoid
Medigap mistakes are easy to make and expensive to reverse. Here are the most common ones — and how to sidestep them:
Mistake #1: Missing Your Open Enrollment Window
This is the costliest error by far. If you delay enrolling in Part B because you’re still working and have employer coverage, your Medigap window shifts — but you must track it carefully. Missing it means underwriting, higher costs, or denial. Set calendar reminders three months before your 65th birthday and consult a Medicare specialist early.
Mistake #2: Choosing Based on Premium Alone
The cheapest Plan N might look great at 65 but could jump significantly in premium by 72 if it uses attained-age pricing. Always ask how a plan’s premium has increased over the last five to ten years before you commit. A broker who specializes in Medicare can pull that rate history for you.
Mistake #3: Assuming Medicare Advantage Is the Same as Medigap
These are fundamentally different products. Medicare Advantage replaces Original Medicare; Medigap supplements it. Advantage plans often have lower premiums but come with network restrictions, prior authorization requirements, and variable out-of-pocket costs. Many people switch from Advantage to Medigap later in life when health needs increase — and then discover they can’t qualify for Medigap due to underwriting. Know the difference before you choose.
Mistake #4: Not Reviewing Your Plan After Major Life Changes
If you move to a new state, your insurer’s rates may change significantly. Some people find substantially lower premiums by switching insurers (which is allowed, subject to underwriting outside your initial window) or by switching from Plan G to the high-deductible version if their health has remained strong.
Mistake #5: Forgetting About Part D
Medigap does not cover prescriptions. If you don’t enroll in a Part D drug plan when first eligible, you’ll face a late enrollment penalty — 1% of the national base premium per month you were without coverage. That penalty follows you for life.
Alternatives to Medigap
Medigap isn’t the only way to manage Medicare cost exposure. Here are the main alternatives:
Medicare Advantage (Part C)
Medicare Advantage plans are offered by private insurers approved by Medicare. They bundle Parts A, B, and usually D into a single plan, often with $0 or low premiums. Many include dental, vision, and hearing. The trade-off: network restrictions, prior authorizations, and potentially higher out-of-pocket costs when you actually get sick. Best for: relatively healthy enrollees who prefer lower premiums and don’t mind managed-care structures.
High-Deductible Plan G
If you’re healthy, the high-deductible version of Plan G offers the same comprehensive coverage as regular Plan G — but only kicks in after you’ve paid $2,870 out of pocket in 2026. Monthly premiums can be as low as $40–$70. Best for: healthy seniors who want catastrophic protection without paying full Medigap premiums every month.
Health Savings Accounts (HSAs) Before Medicare
If you’re still working and enrolled in a high-deductible health plan (HDHP) before Medicare, maximizing your HSA contributions ($4,300 individual / $8,550 family in 2026, per IRS guidelines) gives you a tax-free pool to pay Medicare costs in retirement. Note: once you enroll in Medicare, you can no longer contribute to an HSA — but you can still spend from it tax-free for qualified medical expenses including Medigap premiums. Best for: pre-retirees who want to build a dedicated healthcare fund.
For more context on how to align your investment strategy with your retirement timeline, our guide on Traditional IRA vs. Roth IRA: Which One Wins for You? covers how tax-advantaged accounts can support your healthcare funding strategy in retirement.
Frequently Asked Questions
Can I be denied a Medigap policy?
Yes — outside of your initial 6-month open enrollment period, insurers in most states can use medical underwriting to deny coverage or charge higher premiums based on your health history. A few states (including New York, Massachusetts, and Connecticut) require guaranteed issue year-round, but most do not.
Does Medigap cover pre-existing conditions?
If you enroll during your open enrollment window, insurers cannot exclude pre-existing conditions. Outside that window, they may impose a waiting period of up to 6 months for pre-existing conditions — or deny coverage altogether.
How much does Medigap typically cost per month?
It varies by plan, age, location, gender, and tobacco use. For a 65-year-old non-smoker, Plan G premiums typically range from $120 to $250 per month nationally. Plan N runs $80 to $180 per month in most markets. High-deductible Plan G can be as low as $40 per month.
Can my Medigap insurer cancel my policy?
As long as you pay your premiums on time and don’t commit fraud, your Medigap policy is guaranteed renewable. The insurer cannot cancel you because you get sick or file frequent claims.
Is Medigap worth it if I’m healthy?
Possibly not in the short term — but the value of Medigap is protection against catastrophic costs, not everyday savings. A single hospital stay without Medigap could cost $5,000–$10,000+ out of pocket. For many retirees, the peace of mind and budget predictability justify the premium, even when they’re healthy.
Is Medigap the Right Move for You?
Medicare Supplement Insurance is one of the most practical tools available to retirees who want financial predictability in their healthcare spending. For most people with Original Medicare, some form of supplemental coverage — whether Medigap or another strategy — is essential to avoid potentially devastating out-of-pocket costs.
The right time to act is before you need it. Your 6-month open enrollment window is the only time you’re guaranteed coverage at standard rates regardless of your health history. Missing that window is a mistake that can follow you for life.
Start by using Medicare’s official comparison tools at medicare.gov, get quotes from at least three insurers, and consider working with an independent Medicare broker who isn’t tied to a single company. Generally speaking, the extra effort during the planning phase saves thousands over the course of your retirement.
This article is for educational purposes only and does not constitute financial, tax, or investment advice. Always consult a licensed financial advisor, CPA, or attorney — as well as a licensed Medicare specialist — before making decisions about your healthcare coverage.