If you're on Medicare and tired of unexpected bills after doctor visits or hospital stays, a Medicare Supplement plan — also called Medigap — is designed to fill those gaps. But the cost of that protection varies enormously, and in 2025, beneficiaries are finding that premiums have shifted enough to warrant a fresh look at what they're paying and whether they're getting the best deal available.
The average monthly premium for a Medigap plan in 2025 depends heavily on which of the standardized plan letters you choose. Plan G, which has become the go-to option for most new Medicare enrollees since Plan F was closed to new entrants in 2020, typically runs between $100 and $200 per month for a 65-year-old, though premiums can climb above $250 or even $300 per month for older enrollees or those in higher-cost states like New York, Florida, or Connecticut. Plan N, a lower-premium alternative that requires small copays ($20 for office visits, $50 for emergency room visits that don't result in inpatient admission), often runs $50 to $80 less per month than Plan G for the same enrollee. Plan K and Plan L are the most affordable options, with premiums sometimes under $80 per month, but they only cover 50% and 75% of certain costs respectively, leaving you with more out-of-pocket exposure.
Plan G's appeal in 2025 is straightforward: it covers virtually everything Medicare doesn't, except the Part B deductible, which is $257 in 2025. Once you've paid that deductible, Plan G covers 100% of Medicare-approved costs for the rest of the year — including the 20% coinsurance that Original Medicare leaves behind, hospital costs beyond Medicare's coverage window, skilled nursing facility coinsurance, and even emergency care during foreign travel (up to plan limits). For someone who sees specialists regularly, manages a chronic condition, or simply wants predictable healthcare costs, that comprehensive coverage can be worth the higher monthly premium compared to Plan N or Plan K.
What many beneficiaries don't realize is that every insurance company selling Medigap is required by federal law to offer the same standardized benefits within each plan letter. A Plan G from Aetna covers exactly the same things as a Plan G from Mutual of Omaha or Blue Cross Blue Shield. The only differences are the premium, the company's financial stability, and any additional perks like gym memberships or nurse hotlines. This means the only rational reason to pay more for the same plan letter is if you have a strong preference for a particular insurer's customer service. Otherwise, shopping aggressively across carriers in your ZIP code can save you $50 to $100 or more per month — which adds up to $600 to $1,200 per year for identical coverage.
The pricing method your insurer uses matters enormously for your long-term costs, and it's one of the most overlooked factors when people enroll. There are three methods: community-rated (everyone in a geographic area pays the same premium regardless of age), issue-age-rated (your premium is based on your age when you first buy the policy and doesn't automatically increase as you get older), and attained-age-rated (your premium increases as you age, typically every year or every few years). Most insurers in most states use attained-age rating, which means a plan that seems affordable at 65 can become significantly more expensive by the time you're 75 or 80. A plan priced at $130 per month at age 65 under attained-age rating might cost $200 or more by age 75, even without general inflation adjustments. Community-rated plans, more common in states like New York and Connecticut, often have higher starting premiums but more predictable long-term costs.
Geography plays a major role in what you'll pay. States with dense urban populations and higher healthcare costs — including California, New York, Florida, and Massachusetts — tend to have higher Medigap premiums across the board. Meanwhile, beneficiaries in rural Midwestern or Southern states may find Plan G premiums closer to $90 to $130 per month at age 65. Some states also have additional consumer protections that affect your ability to switch plans. Thirteen states currently have a birthday rule that gives you a 30-day window each year around your birthday to switch to an equal or lesser Medigap plan without medical underwriting — meaning insurers can't deny you or charge you more based on health conditions. Those states are 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 feel you're overpaying, your birthday window is a valuable opportunity to shop for a lower premium on the same plan letter.
Tobacco use is another significant cost factor. Most states allow insurers to charge tobacco users up to 10% to 15% more than non-smokers for the same Medigap plan. Some insurers charge even more where state law permits. If you've quit smoking since you first enrolled in a Medigap plan, it may be worth contacting your insurer or shopping for a new plan — though outside of guaranteed issue periods or state birthday rule windows, you'll typically need to pass medical underwriting to switch.
The best time to enroll in a Medigap plan is during your 6-month Medigap Open Enrollment Period, which begins the month you turn 65 and are enrolled in Medicare Part B. During this window, insurers cannot deny you coverage or charge you more based on any pre-existing health conditions. Once this window closes, you generally lose federal guaranteed issue rights and insurers can medically underwrite you — meaning they can reject your application or charge higher premiums based on your health history. This is why locking in a plan during that initial enrollment window is so important, even if you're healthy and feel like you might not need the coverage yet.
For beneficiaries already enrolled in a Medigap plan who want to know if they're overpaying, the State Health Insurance Assistance Program (SHIP) offers free, unbiased counseling in every state. SHIP counselors can pull current premium quotes from all licensed insurers in your area and help you compare options side by side. You can reach SHIP through Medicare.gov or by calling 1-800-MEDICARE. Additionally, the Medicare Plan Finder tool at Medicare.gov allows you to compare Medigap premiums by ZIP code, though it doesn't include every insurer in every market, so supplementing that search with direct insurer quotes or a licensed independent broker is advisable.
One cost-saving strategy worth considering in 2025 is the high-deductible version of Plan G, known as HDG. This plan carries the same comprehensive benefits as standard Plan G but requires you to pay a deductible — $2,870 in 2025 — before the plan begins paying. In exchange, monthly premiums are dramatically lower, often in the range of $30 to $60 per month for a 65-year-old. For beneficiaries who are generally healthy and have some savings to cover the deductible in a bad year, HDG can offer significant premium savings while still providing a ceiling on catastrophic out-of-pocket costs. The math works in your favor if you go most years without hitting the deductible, and the worst-case scenario is still capped at $2,870 — far less than what an uninsured hospital stay could cost.
Ultimately, the right Medigap plan in 2025 isn't the one with the lowest premium or the most comprehensive coverage in isolation — it's the one that fits your health usage patterns, your financial situation, and your tolerance for uncertainty. A healthy 65-year-old with modest savings might do well with Plan N or HDG Plan G. Someone managing multiple chronic conditions who sees specialists frequently may find that standard Plan G's higher premium is more than offset by the elimination of copays and coinsurance. Running the numbers with a SHIP counselor or an independent broker who can quote multiple carriers is the most reliable way to find your answer.