Medicare Supplement Plan G: What It Covers, What It Costs, and Who Needs It

If you've spent any time 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 Plan F was closed to new enrollees born after January 1, 1955, Plan G has stepped in as the most comprehensive Medigap option available to most people turning 65 today. But comprehensive doesn't automatically mean right for you. Understanding exactly what Plan G covers, what it costs in real dollar terms, and how it compares to alternatives like Plan N can help you make a decision you won't regret when a major health event hits.

Medicare Supplement Plan G is a standardized policy, which means the benefits are identical regardless of which private insurance company sells it to you. That's a critical point. Whether you buy Plan G from Mutual of Omaha, AARP/UnitedHealthcare, Cigna, or a smaller regional carrier, the coverage itself is exactly the same — set by federal law. What differs is the monthly premium, the company's financial stability, and their customer service reputation. In 2025, Plan G covers the Medicare Part A hospital deductible ($1,676 per benefit period), Part A coinsurance and hospital costs up to an additional 365 days after Medicare benefits are exhausted, Part A hospice care coinsurance or copayments, Part B coinsurance or copayments (typically 20% of outpatient costs), the first three pints of blood, skilled nursing facility care coinsurance, and 80% of emergency medical costs during foreign travel (up to plan limits, after a $250 deductible). The one gap Plan G does not fill is the Medicare Part B deductible, which is $257 in 2025. You pay that once per year yourself.

To understand why that single uncovered deductible matters less than it might seem, consider what Plan G actually protects you from. Without any supplement, a Medicare beneficiary who has a serious illness or surgery faces the Part A deductible of $1,676 — and that resets every benefit period, not just once a year. If you're hospitalized twice in a year in separate benefit periods, you could owe $3,352 in deductibles alone. Add the 20% coinsurance on outpatient services with no cap, and a cancer diagnosis or cardiac event could generate tens of thousands of dollars in out-of-pocket costs. Plan G eliminates virtually all of that exposure in exchange for a predictable monthly premium. For most people on fixed incomes, that trade-off — known costs versus unknown costs — is exactly what makes Plan G appealing.

Now let's talk real numbers on premiums, because this is where people often get surprised. Plan G premiums in 2025 vary enormously based on three factors: your age, your ZIP code, and how the insurer prices its policies. Insurers use one of three pricing methods. 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 solely because you get older. Issue-age-rated plans set your premium based on the age you are when you first enroll and don't raise it as you age, though they do adjust for inflation. Attained-age-rated plans start lower but increase every year as you get older — these are the most common and can become significantly more expensive in your 70s and 80s. A 65-year-old woman in a mid-sized city might pay $110 to $150 per month for Plan G from a competitive carrier. That same plan for a 72-year-old man in a high-cost urban area could run $200 to $280 per month or more. Tobacco users typically pay 10% to 20% higher premiums with most carriers.

Plan G's closest competitor is Plan N, and the comparison is worth taking seriously. Plan N covers the same benefits as Plan G with two exceptions: you pay up to $20 per doctor visit 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 — the additional amount (up to 15% above Medicare's approved rate) that doctors who don't accept Medicare assignment can legally charge. Plan N premiums are typically $30 to $60 per month lower than Plan G premiums for the same person. If you're healthy, rarely see specialists, and live in a state where most doctors accept Medicare assignment, Plan N can save you real money over time. But if you see multiple specialists regularly, or live in a state with higher rates of non-participating providers, Plan G's predictability may be worth the higher premium. There's no universal right answer — it depends on your health patterns and risk tolerance.

The single most important timing decision you'll make about Plan G is when you enroll. Federal law gives you a 6-month Medigap Open Enrollment Period that begins the first month you are both 65 or older and enrolled in Medicare Part B. During this window, no insurance company can deny you coverage, charge you more because of pre-existing conditions, or make you wait for coverage to begin. Once that window closes, you're subject to medical underwriting in most states — meaning insurers can review your health history and decline to cover you, or charge significantly higher premiums, for conditions like diabetes, heart disease, COPD, or prior cancer. This is not a window you want to miss. If you delayed Part B enrollment because you had employer coverage, your open enrollment window starts when your Part B coverage begins, not when you turn 65.

A handful of states offer additional protections worth knowing about. If you live in California, Idaho, Illinois, Kentucky, Louisiana, Maine, Maryland, Missouri, Nevada, New Jersey, New York, Oklahoma, or Oregon, you may have a birthday rule — a 30-day window each year around your birthday during which you can switch to a different Medigap plan of equal or lesser benefits without medical underwriting. New York and Connecticut go further, offering guaranteed issue rights year-round regardless of health status. If you're in one of these states and locked into a plan with a carrier that's been raising rates aggressively, you may have more flexibility to switch than you realize.

One expensive mistake people make is assuming that the cheapest Plan G quote they find online is the best long-term value. Premium rate history matters. Some carriers attract new enrollees with low initial premiums and then implement steep annual increases — 8%, 10%, even 12% in some years — once they've built up their book of business. Before you commit, ask the agent or carrier for the plan's rate increase history over the past five years. Carriers with a track record of 3% to 5% annual increases are generally more stable than those with erratic or high increases. Your state's Department of Insurance website typically publishes rate increase filings, which are public record. Checking that history takes 20 minutes and can save you hundreds of dollars annually down the road.

Finally, it's worth addressing who Plan G may not be the right fit for. If you're in excellent health, have significant savings, and are comfortable managing unpredictable out-of-pocket costs, a Medicare Advantage plan with a lower premium might serve you better financially — at least in years when you're healthy. If your income qualifies you for a Medicare Savings Program or Extra Help, those programs may cover costs that make a Medigap policy redundant. And if you're already past your open enrollment window and have significant health conditions, the premium you'd be quoted for Plan G after underwriting might make the math less favorable. The right supplement plan is the one that fits your actual health situation, your financial cushion, and your tolerance for uncertainty — not simply the one with the most coverage on paper.