Choosing a Medicare Supplement plan comes down to three decisions: how much financial protection you want, which insurance company to buy from, and when to enroll. Most people narrowing down their options are comparing Plan G and Plan N, which offer the most comprehensive coverage among plans still available to new enrollees. The right choice depends on how often you see doctors, whether you travel, and how much predictability you want in your healthcare costs.
Medigap vs. Medicare Advantage: The First Fork
Before comparing individual supplement plans, make sure a Medigap policy is the right path for you. Medicare Supplement plans and Medicare Advantage plans solve the same problem (covering costs that Original Medicare doesn’t) but work in completely different ways.
With a Medigap plan, you stay on Original Medicare and can see any doctor in the country who accepts Medicare. There’s no network to worry about, no referrals needed, and your out-of-pocket costs are minimal because the supplement covers most or all of what Medicare leaves behind. The trade-off: you pay a monthly premium for the supplement, and you’ll need to buy a separate Part D plan for prescription drug coverage.
Medicare Advantage plans typically bundle drug coverage and sometimes dental or vision into one package, often with lower monthly premiums. But you’re locked into a provider network, may need referrals to see specialists, and face higher out-of-pocket costs when you actually use care. If you travel frequently, live part of the year in another state, or want the freedom to see any Medicare provider without restrictions, a Medigap plan is usually the better fit.
How the Lettered Plans Work
Medigap plans are standardized by the federal government and labeled with letters: Plans A through N. A Plan G from one insurance company covers exactly the same benefits as a Plan G from another company. The only differences between carriers are price, customer service, and financial stability. This standardization makes comparison shopping straightforward once you’ve picked a plan letter.
Three states use their own systems instead of the federal letter format: Massachusetts, Minnesota, and Wisconsin. If you live in one of those states, the plan names and structures will look different, but the overall approach to choosing is similar.
Among the lettered plans, Plan G and Plan N are the most popular choices for new enrollees. Plan F, which used to be the go-to option, is no longer available to anyone who became eligible for Medicare after January 1, 2020.
Plan G vs. Plan N: The Core Decision
Plan G is the most comprehensive Medigap plan available to new enrollees. It covers your share of hospital costs, skilled nursing facility care, Part B coinsurance, hospice care, and the first three pints of blood. It also covers Part B excess charges, which are the extra amounts some doctors can bill above Medicare’s approved rate. With Plan G, your only remaining out-of-pocket cost for the year is the annual Part B deductible ($257 in 2025). After that, virtually everything is covered.
Plan N covers the same core benefits but with two gaps. First, it doesn’t cover Part B excess charges. If a doctor doesn’t accept Medicare assignment and bills above the approved amount, you pay the difference. Second, Plan N requires small copayments for certain services: up to $20 for some office visits and up to $50 for emergency room visits that don’t result in an inpatient admission. In exchange for these minor cost-sharing requirements, Plan N premiums are noticeably lower than Plan G premiums, often by $30 to $60 per month depending on your area and age.
For someone who rarely sees doctors and wants to save on premiums, Plan N can be a smart choice. The excess charge risk is small in practice because the vast majority of doctors accept Medicare assignment. But if you want the simplest, most predictable coverage with almost zero surprise bills, Plan G is the safer bet.
The High-Deductible Option
There’s also a High Deductible version of Plan G for people who are comfortable absorbing routine costs in exchange for lower premiums. With this version, you pay all Medicare cost-sharing out of pocket until you hit a $2,870 annual deductible (the 2025 amount). After that, the plan covers everything just like standard Plan G. Monthly premiums for High Deductible Plan G are significantly lower, sometimes under $50 per month. This option works well for healthy people who want catastrophic protection without paying for coverage they rarely use.
When to Enroll Matters More Than Which Plan
Your enrollment timing has a bigger impact on your options and costs than most people realize. The Medigap Open Enrollment Period is a six-month window that begins the first day of the month you turn 65 and are enrolled in Medicare Part B. During this window, insurance companies must sell you any Medigap plan they offer at the standard price, regardless of your health history. They cannot charge you more for pre-existing conditions or deny you coverage.
Once that six-month window closes, you lose this federal protection. Insurance companies can use medical underwriting, which means they can review your health history, charge higher premiums based on existing conditions, or refuse to sell you a policy entirely. The difference in cost can be dramatic. Someone with diabetes or a heart condition who applies outside the open enrollment period might pay significantly more, or be unable to get coverage at all.
If you’re approaching 65 and planning to enroll in Part B, start comparing Medigap plans a few months before your birthday so you’re ready to buy during this critical window.
Guaranteed Issue Rights After Open Enrollment
If you missed your open enrollment window or need to switch plans later, certain life events give you “guaranteed issue rights,” which temporarily restore your protection from medical underwriting. You get 63 days from the triggering event to buy a Medigap plan without health screening. Qualifying situations include:
- Losing group health coverage that was paying your Medicare cost-sharing (such as retiree insurance from a former employer)
- Leaving a Medicare Advantage plan within 12 months of first enrolling
- Moving out of your plan’s service area if you have a Medicare Advantage plan, Medicare SELECT policy, or PACE program
- Your plan ending coverage or committing fraud through no fault of your own
These rights are narrowly defined. Voluntarily dropping a Medicare Advantage plan after the first year, for example, does not automatically give you guaranteed issue rights in most states. Planning your initial enrollment carefully is far easier than trying to course-correct later.
Comparing Insurance Companies
Since Plan G from one company covers the same benefits as Plan G from another, your comparison between carriers comes down to three factors: premium pricing, rate stability over time, and financial strength.
Premiums for the same plan letter can vary by hundreds of dollars per year between companies in the same zip code. Get quotes from at least four or five carriers. Your state’s department of insurance or State Health Insurance Assistance Program (SHIP) can provide comparison tools or free counseling to help you shop.
Pay attention to how a company prices its plans. Some insurers use “attained-age” pricing, where premiums increase as you get older. Others use “issue-age” pricing, where your rate is based on your age when you first buy the policy and only rises with inflation, not aging. Issue-age pricing tends to cost more upfront but less over time. Not all pricing methods are available in every state.
Financial stability matters because you’re buying a policy you may hold for decades. You can look up an insurer’s financial strength rating through AM Best, which grades companies on a scale from A++ (superior) down through lower ratings. Sticking with a company rated A- or higher gives you reasonable confidence the insurer will be around to pay claims 15 or 20 years from now. You can search ratings for free at AM Best’s website.
Practical Steps to Make Your Decision
Start by deciding between Plan G and Plan N. If predictability matters more than saving on premiums, choose Plan G. If you’re comfortable with small copays and want to keep your monthly costs lower, Plan N is a solid alternative. If you’re in good health and want the lowest possible premium, consider High Deductible Plan G.
Next, gather quotes from multiple insurers in your zip code. Compare not just the current premium but the company’s pricing method and rate increase history. Some state insurance departments publish historical rate increase data, which tells you how aggressively a company has raised prices in past years.
Finally, remember that you’ll need a standalone Part D prescription drug plan alongside any Medigap policy. Factor that premium into your total monthly budget when comparing the Medigap route against Medicare Advantage alternatives. For many people, the combination of Original Medicare, a Medigap plan, and a Part D plan provides the most flexible, predictable coverage available, especially if you value the ability to see any doctor nationwide without network hassles.