Medicare Supplement Plan G: What It Covers and What It Costs

If you've been researching Medicare Supplement insurance — also called Medigap — you've probably noticed that Plan G keeps coming up as the top recommendation. That's not an accident. Since Medicare Supplement Plan C and Plan F were closed to new enrollees who became eligible for Medicare on or after January 1, 2020, Plan G has stepped into the role of the most comprehensive Medigap policy available to most beneficiaries. Understanding exactly what it covers, what it costs, and how it compares to alternatives like Plan N can save you thousands of dollars over the course of your retirement.

Original Medicare — Parts A and B — covers a broad range of hospital and medical services, but it does not cap your out-of-pocket spending. In 2025, the Medicare Part A hospital deductible is $1,676 per benefit period, and there is no limit on how many benefit periods you can have in a year. Part B covers 80% of approved outpatient costs after you meet the annual deductible of $257, leaving you responsible for the remaining 20% with no ceiling. A single serious illness or surgery could expose you to tens of thousands of dollars in cost-sharing. Plan G is specifically designed to close almost all of those gaps.

Here is what Medicare Supplement Plan G actually covers in 2025: the Medicare Part A deductible ($1,676 per benefit period), Part A coinsurance and hospital costs for up to 365 days after Medicare benefits are exhausted, Part A hospice care coinsurance or copayments, skilled nursing facility coinsurance (which runs $209.50 per day for days 21 through 100 in 2025), Part B coinsurance or copayments (that 20% you'd otherwise owe), Part B excess charges (the amount a doctor who doesn't accept Medicare assignment can charge above the Medicare-approved amount, up to 15%), and foreign travel emergency care up to plan limits — typically 80% of costs after a $250 deductible, up to a $50,000 lifetime maximum. The only gap Plan G does not fill is the Medicare Part B annual deductible, which is $257 in 2025. Once you've paid that amount out of pocket at the start of each year, Plan G covers the rest.

That $257 annual deductible is the critical distinction between Plan G and the now-closed Plan F. Plan F covered everything, including that deductible, but it's no longer available to anyone who became eligible for Medicare after December 31, 2019. If you were already enrolled in Medicare before 2020, you may still be able to purchase Plan F, but premiums for Plan F tend to run $30 to $60 per month higher than Plan G — meaning you'd pay $360 to $720 more per year in premiums to avoid a $257 deductible. For most people, Plan G is the better financial deal even when Plan F is technically available.

Premium costs for Plan G vary significantly depending on three factors: your age, where you live, and which insurance company you choose. Nationally, monthly premiums in 2025 range from approximately $100 per month for a 65-year-old in a lower-cost state to $300 or more per month for older enrollees in high-cost markets like New York or Massachusetts. Insurance companies are allowed to price Medigap policies using one of three methods: community rating (everyone pays the same regardless of age), issue-age rating (your premium is based on your age when you first buy the policy and doesn't increase as you get older), and attained-age rating (your premium increases as you age). Attained-age policies often look cheapest at 65 but can become the most expensive option by your 70s and 80s. Asking an insurer which rating method they use is one of the most important questions you can ask before signing up.

Because Medigap plans are standardized by the federal government, the Plan G benefits are identical regardless of which insurance company sells the policy. A Plan G from Mutual of Omaha covers exactly the same services as a Plan G from Aetna, UnitedHealthcare, or your state's Blue Cross Blue Shield plan. The only meaningful differences between insurers are premium price, financial stability ratings, and customer service reputation. This means shopping around is entirely safe — you are not giving up any coverage by choosing a lower-premium insurer, as long as the plan is labeled Plan G and sold in your state.

The best time to buy Plan G — and the time when you are guaranteed the lowest premiums and cannot be turned down for pre-existing conditions — is during your Medigap Open Enrollment Period. This six-month window begins the month you turn 65 and are enrolled in Medicare Part B. During this period, insurers must sell you any Medigap policy they offer at the same price as a healthy enrollee, regardless of your health history. Outside of this window, insurers in most states can use medical underwriting, meaning they can charge you more or deny coverage based on conditions like diabetes, heart disease, or prior cancer treatment. Missing your open enrollment window is one of the most costly Medicare mistakes a beneficiary can make.

A handful of states offer additional protections. If you live in California, Idaho, Illinois, Kentucky, Louisiana, Maine, Maryland, Missouri, Nevada, New Jersey, New York, Oklahoma, or Oregon, you have a birthday rule or similar guaranteed-issue right that allows you to switch Medigap plans — typically within 30 days of your birthday — without medical underwriting. New York and Massachusetts go further, requiring insurers to offer Medigap policies on a guaranteed-issue basis year-round. If you live in one of these states and are currently in a plan that no longer fits your needs, you may have more flexibility than you realize.

Plan G is not the right choice for everyone. If you are generally healthy, rarely see specialists, and want to keep monthly premiums low, Plan N may be worth comparing. Plan N also covers the Part A deductible and skilled nursing coinsurance, but it does not cover Part B excess charges and requires copayments of up to $20 for office visits and up to $50 for emergency room visits that don't result in inpatient admission. Plan N premiums typically run $30 to $70 per month less than Plan G. If you see doctors who all accept Medicare assignment — meaning they agree not to charge excess fees — and your visit frequency is low, Plan N's lower premium could result in net savings. But if you see specialists frequently or live in an area where many physicians don't accept Medicare assignment, Plan G's comprehensive coverage may cost less overall.

To compare Plan G premiums in your area, the Medicare Plan Finder tool at Medicare.gov allows you to search Medigap policies by ZIP code. Your State Health Insurance Assistance Program, known as SHIP, offers free one-on-one counseling from trained volunteers who can walk you through plan options without trying to sell you anything. You can find your local SHIP contact through the Eldercare Locator at eldercare.acl.gov or by calling 1-800-MEDICARE. These free resources exist specifically to help you make this decision without pressure, and using them before you commit to any Medigap policy is time well spent.