If you're on Original Medicare in 2026, you already know the coverage has gaps — and those gaps can be expensive. The Part A hospital deductible alone is $1,676 per benefit period in 2026, and there's no cap on out-of-pocket costs under Original Medicare alone. That's where Medicare Supplement Insurance, commonly called Medigap, comes in. These standardized private insurance plans are designed to cover what Medicare Parts A and B leave behind, and choosing the right one can mean the difference between financial security and a surprise medical bill that wipes out your savings.
Medigap plans are standardized by the federal government, meaning a Plan G from Aetna covers exactly the same benefits as a Plan G from Mutual of Omaha or Blue Cross Blue Shield. What differs between insurers is the monthly premium you pay. In 2026, Plan G premiums for a 65-year-old non-smoker can range from roughly $100 to over $200 per month depending on your state and the insurer — sometimes for the exact same coverage. That spread makes comparison shopping not just worthwhile but essential. The Medicare Plan Finder tool at Medicare.gov allows you to compare Medigap premiums by zip code, and your State Health Insurance Assistance Program (SHIP) can walk you through options at no cost.
Plan G has become the gold standard for new Medicare enrollees since Plan F was closed to people who became eligible for Medicare on or after January 1, 2020. Plan G covers the Part A deductible ($1,676 per benefit period in 2026), Part A coinsurance and hospital costs up to an additional 365 days after Medicare benefits are exhausted, Part B coinsurance or copayments, the first three pints of blood, Part A hospice care coinsurance, skilled nursing facility care coinsurance, and foreign travel emergency care (up to plan limits). The only standard cost Plan G does not cover is the Part B deductible, which is $257 in 2026. After you pay that deductible once per year, Plan G essentially covers the rest of your Medicare-approved medical expenses for the year. For anyone with chronic conditions, frequent specialist visits, or planned surgeries, Plan G's predictability is its biggest selling point.
Plan N is the second most popular Medigap option in 2026 and deserves serious consideration from healthier beneficiaries who want lower premiums in exchange for modest cost-sharing. Like Plan G, Plan N covers the Part A deductible and most major cost categories. The key differences: you pay up to $20 per office visit and up to $50 per emergency room visit (waived if you're admitted). Plan N also does not cover Part B excess charges — the additional amount some doctors who don't accept Medicare assignment can legally charge above the Medicare-approved amount. If you live in a state where most physicians accept Medicare assignment (which you can verify at Medicare.gov's physician compare tool), excess charges may rarely apply to you. For someone who sees a doctor only a few times a year, Plan N's premium savings — often $30 to $60 per month less than Plan G — can more than offset those copays.
Plan High-Deductible G (HDG) is a lower-profile option that's worth understanding. It carries the same benefits as standard Plan G but requires you to pay a deductible of $2,870 in 2026 before the plan begins paying. In exchange, monthly premiums can be as low as $30 to $50 per month in many markets. This plan functions almost like a catastrophic backstop — you handle routine costs yourself, but you're protected from truly ruinous expenses. HDG works best for people who are generally healthy, have sufficient savings to cover the deductible in a bad year, and want the lowest possible monthly premium. It's not the right fit for someone managing multiple chronic conditions with regular hospitalizations or specialist care.
Plan K and Plan L are cost-sharing plans that cover only a percentage of certain benefits — Plan K covers 50% of several cost categories and has a $7,220 out-of-pocket limit in 2026, while Plan L covers 75% with a $3,610 limit. These plans have lower premiums but expose you to more unpredictable costs, and they're generally less popular for that reason. Plan M and Plan D round out the standardized options but have limited availability in many states. Most beneficiaries comparing plans will find the real decision comes down to Plan G versus Plan N, with HDG as a third option for the cost-conscious and healthy.
Timing matters enormously when it comes to Medigap enrollment. Your best window is 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 pre-existing conditions — this is called guaranteed issue. Once that window closes, insurers in most states can use medical underwriting, meaning they can reject your application or charge higher premiums based on your health history. If you miss your open enrollment window and later want to switch Medigap plans, you may face underwriting unless a Special Enrollment Period applies — such as losing employer coverage or your current plan leaving the market.
Thirteen states have enacted birthday rules that give beneficiaries an additional annual window to switch Medigap plans without medical underwriting: California, Idaho, Illinois, Kentucky, Louisiana, Maine, Maryland, Missouri, Nevada, New Jersey, New York, Oklahoma, and Oregon. In these states, you typically have a 30-day window around your birthday each year to switch to a plan with equal or lesser benefits from any insurer, regardless of your health status. If you live in one of these states and have been locked into a high-premium plan, your birthday window may be your opportunity to shop for a better rate on the same coverage.
Premium pricing methods also affect your long-term costs in ways that aren't obvious at first glance. Insurers use three methods: community-rated (everyone pays the same regardless of age), issue-age-rated (your premium is based on your age when you buy), and attained-age-rated (premiums increase as you get older). Attained-age-rated plans often have the lowest initial premiums but can become significantly more expensive over time. Community-rated plans, more common in states like New York and Connecticut, tend to be more expensive upfront but more stable over decades. When comparing plans, ask each insurer which rating method they use and request their historical rate increase data — a plan with a 3% average annual increase is very different from one averaging 8%.
To get the most accurate comparison, contact at least three to five insurers directly and use Medicare.gov's Medigap policy search tool. Your state's SHIP counselors — reachable through the Eldercare Locator at 1-800-677-1116 — can provide free, unbiased guidance and help you decode the fine print. Your state insurance commissioner's office can also verify that any insurer you're considering is licensed in your state and has a clean complaint record. The bottom line: because every Plan G is legally identical in benefits, the only rational reason to pay more is if a particular insurer has a significantly better rate-increase history or customer service record. Do the homework now, and you can lock in coverage that protects you for years to come.