If you've just turned 65 or are approaching Medicare eligibility, you've probably heard the term 'Medigap' thrown around alongside phrases like 'Medicare Supplement' and 'Plan G' and 'Plan N.' It all sounds like alphabet soup until you realize what's actually at stake: without a Medigap policy, Original Medicare leaves you exposed to a 20% coinsurance on virtually every doctor visit and outpatient procedure, with no annual cap on what you can owe. For someone undergoing chemotherapy, recovering from a hip replacement, or managing a chronic condition, that 20% can add up to tens of thousands of dollars in a single year. Medigap exists to fill those gaps — and choosing the right plan is one of the most consequential financial decisions you'll make in retirement.
Medigap plans are sold by private insurance companies, but the benefits for each plan letter are standardized by federal law in most states. That means a Plan G sold by Aetna covers exactly the same benefits as a Plan G sold by Mutual of Omaha or Blue Cross Blue Shield. What differs between insurers is the monthly premium, the company's financial stability, and the quality of customer service. This standardization is actually a gift to consumers — it means you can comparison shop on price alone once you've decided which plan letter fits your needs, rather than trying to decode different benefit structures from different companies.
For most new Medicare enrollees in 2026, the conversation about Medigap starts and ends with two plans: Plan G and Plan N. Plan G is the gold standard of comprehensive coverage. It pays the Part A hospital deductible ($1,676 in 2026), Part A coinsurance and hospital costs, Part B coinsurance and copayments, the first three pints of blood, Part A hospice care coinsurance, skilled nursing facility coinsurance, and foreign travel emergency coverage (up to plan limits). The only thing Plan G does not cover is the Part B deductible, which is $257 in 2026. Once you've paid that $257 out of pocket at the start of the year, Plan G essentially covers the rest. For someone with frequent doctor visits, specialist appointments, or ongoing treatments, this near-total coverage provides both financial protection and the peace of mind of knowing your costs are predictable.
Plan N is the runner-up and deserves serious consideration if you're in reasonably good health and want to lower your monthly premium. Plan N covers the same broad categories as Plan G — Part A deductible, coinsurance, skilled nursing, foreign travel — but it introduces two cost-sharing elements: a copay of up to $20 for office visits and up to $50 for emergency room visits that don't result in an inpatient admission. Plan N also does not cover Part B excess charges, which are the additional fees some doctors charge above Medicare's approved amount. In states that prohibit balance billing — meaning doctors cannot charge more than Medicare's approved rate — the excess charge issue is largely moot. But in states where balance billing is allowed, you'll want to confirm your doctors accept Medicare assignment before relying on Plan N. The premium savings with Plan N can be meaningful: depending on your age, gender, and location, Plan N premiums may run $30 to $80 per month less than Plan G, which translates to $360 to $960 in annual savings. Whether that trade-off makes sense depends on how often you visit the doctor.
Data Snapshot: According to CMS.gov data, there were approximately 14.5 million Medigap policyholders in the United States as of the most recent reporting period, with Plan G and Plan F (now closed to new enrollees who became eligible for Medicare after January 1, 2020) accounting for the largest share of enrollment. CMS data also shows that the average monthly premium for a 65-year-old female non-smoker enrolled in Plan G ranges from roughly $100 to $200 depending on the state and insurer, with significant variation even within the same ZIP code. This spread underscores why comparing multiple quotes — not just accepting the first plan you're offered — can save a beneficiary hundreds of dollars annually without sacrificing a single dollar of coverage.
You may have heard about Plan F, which was the most popular Medigap plan for decades because it covered everything including the Part B deductible. If you were already enrolled in Medicare before January 1, 2020, you can still purchase Plan F, and if you already have it, you can keep it. But if you became eligible for Medicare on or after January 1, 2020, Plan F is off the table for you by law. Plan G is the functional equivalent for new enrollees — the only difference is that $257 Part B deductible, which most financial advisors consider a reasonable trade-off given that Plan G premiums are typically lower than Plan F premiums were for comparable coverage.
There's also Plan K and Plan L, which are high-deductible-style options that cover a percentage of costs rather than 100% of them. Plan K covers 50% of several benefit categories and has an out-of-pocket limit of $7,220 in 2026; Plan L covers 75% with a $3,610 out-of-pocket limit. These plans carry the lowest premiums of any Medigap option, but they expose you to significant cost-sharing before the out-of-pocket limit kicks in. They're worth considering only if you're extremely healthy, have substantial liquid savings to cover potential gaps, and are primarily looking to protect against catastrophic costs rather than routine expenses. For most seniors, the premium savings don't justify the financial exposure.
High-deductible Plan G is another option that's gained attention in recent years. It works like standard Plan G but requires you to pay a deductible — $2,870 in 2026 — before the plan begins paying. In exchange, the monthly premiums are dramatically lower, sometimes $40 to $60 per month compared to $150 or more for standard Plan G. If you're healthy and rarely use medical services, high-deductible Plan G can be a smart way to maintain catastrophic coverage while keeping premiums low. The math works in your favor in years when you stay healthy; in years when you have significant medical needs, you'll pay more out of pocket before coverage kicks in. Some beneficiaries pair high-deductible Plan G with a health savings account strategy, though it's worth noting that once you're enrolled in Medicare, you can no longer contribute to an HSA.
Timing your Medigap enrollment correctly is arguably as important as choosing the right plan letter. Your Medigap Open Enrollment Period begins the first month you're both 65 or older and enrolled in Medicare Part B, and it lasts for six months. During this window, insurers must sell you any Medigap plan they offer at the same price they'd charge a healthy person — they cannot deny you coverage or charge you more based on pre-existing conditions. Once this window closes, you lose guaranteed issue rights in most states, and insurers can use medical underwriting to charge you higher premiums or deny coverage altogether. Missing this window is one of the most costly mistakes a new Medicare beneficiary can make.
If you're past your initial enrollment window and want to switch Medigap plans, your options depend heavily on where you live. Most states require you to pass medical underwriting if you want to change plans outside of a qualifying event. However, a growing number of states have enacted what's known as the 'birthday rule,' which gives you a 30-day window each year around your birthday to switch to a Medigap plan with equal or lesser benefits without medical underwriting. States with birthday rule protections currently include California, Idaho, Illinois, Kentucky, Louisiana, Maine, Maryland, Missouri, Nevada, New Jersey, New York, Oklahoma, and Oregon. If you live in one of these states and are currently enrolled in a Medigap plan with higher premiums than you'd like, your birthday window may be your opportunity to shop for a better rate.
Premium pricing structures are another factor that rarely gets explained clearly. Medigap insurers use three different methods to set premiums. Community-rated plans charge everyone the same premium regardless of age — these tend to be more expensive when you're young but don't increase as you age. Issue-age-rated plans base your premium on the age you were when you first enrolled, and premiums don't increase as you get older (though they may increase due to inflation). Attained-age-rated plans start with the lowest premiums but increase as you age — these are the most common type and can become quite expensive in your 80s. Understanding which pricing method an insurer uses is critical to evaluating the long-term cost of a plan, not just the initial monthly premium.
One practical step that many beneficiaries overlook: call your state's State Health Insurance Assistance Program, known as SHIP. SHIP counselors are trained, unbiased volunteers who can walk you through Medigap options specific to your state, help you compare quotes, and answer questions about your specific health situation — all at no cost to you. You can find your state's SHIP contact information at shiphelp.org. This is not a sales call; SHIP counselors do not sell insurance and have no financial incentive to steer you toward any particular plan. For a decision this important, having an objective expert in your corner is worth the phone call.
Ultimately, the 'best' Medigap plan is the one that matches your health profile, your financial situation, and your tolerance for uncertainty. If you see specialists regularly, take expensive medications that require infusions or outpatient procedures, or simply want to know exactly what your healthcare will cost each month, Plan G is likely your best choice. If you're healthy, active, and comfortable with modest copays in exchange for lower premiums, Plan N deserves a serious look. And if you're on a tight fixed income and primarily want protection against a catastrophic medical event, high-deductible Plan G may offer the right balance. The worst outcome is doing nothing — staying on Original Medicare alone and hoping for the best. With the right Medigap plan in place, you can see any doctor who accepts Medicare anywhere in the country, without network restrictions, and without the fear of a medical bill that wipes out your savings.