Medicare Supplement Plans Compared: Which Medigap Plan Is Best?

Original Medicare, as great as it is for provider access, has a structural problem: no out-of-pocket maximum. You pay 20% of approved costs for Part B services indefinitely. For a healthy year with a couple of doctor visits, that's nothing. For a year with cancer treatment, a major surgery, or a prolonged hospitalization, that 20% can be catastrophic.

Medigap (Medicare Supplement insurance) was created to fill those gaps. It's private insurance—sold by companies like AARP/UnitedHealthcare, Mutual of Omaha, Humana, Cigna, Aetna, Blue Cross Blue Shield, and hundreds of smaller insurers—that pays some or all of what Original Medicare leaves unpaid.

The key feature of Medigap: in most states, the benefit structure is standardized by CMS. Every Medigap Plan G in California has exactly the same coverage as every Medigap Plan G in Florida. The only real variable is the premium—and premiums can vary by hundreds of dollars per year between insurers for identical coverage.

This matters. A lot. Comparison shopping is genuinely worth your time.

As of 2020, newly eligible Medicare beneficiaries can choose from Plans A, B, D, G, K, L, M, and N. Plans C and F are no longer available to anyone who became Medicare-eligible after January 1, 2020 (because they covered the Part B deductible, which was phased out for new enrollees). If you were eligible before 2020, you can still keep or switch to Plans C and F.

### The Coverage Grid

| Benefit | Plan A | Plan B | Plan D | Plan G | Plan K | Plan L | Plan M | Plan N | |---|---|---|---|---|---|---|---|---| | Part A coinsurance & hospital costs | 100% | 100% | 100% | 100% | 100% | 100% | 100% | 100% | | Part B coinsurance or copay | 100% | 100% | 100% | 100% | 50% | 75% | 100% | 100%* | | Blood (first 3 pints) | 100% | 100% | 100% | 100% | 50% | 75% | 100% | 100% | | Part A hospice care coinsurance | 100% | 100% | 100% | 100% | 50% | 75% | 100% | 100% | | Skilled nursing coinsurance | No | No | 100% | 100% | 50% | 75% | 100% | 100% | | Part A deductible | No | 100% | 100% | 100% | 50% | 75% | 50% | 100% | | Part B deductible | No | No | No | No | No | No | No | No | | Part B excess charges | No | No | No | 100% | No | No | No | No | | Foreign travel emergency | No | No | 80% | 80% | No | No | 80% | 80% |

*Plan N: you pay up to $20 copay for office visits and up to $50 for emergency room visits (waived if admitted)

### Plans K and L: The Cost-Sharing Versions

Plans K and L have lower premiums because they don't cover everything at 100%—you share costs with the plan. They're designed for people who want catastrophic protection but are comfortable with some cost-sharing.

Plan K covers 50% of most benefits. Plan L covers 75%. Both have annual out-of-pocket limits ($7,220 for Plan K, $3,610 for Plan L in 2026—these adjust annually). Once you hit the limit, the plan pays 100% for the rest of the year.

### Plans K and L Might Make Sense If

You want lower premiums than Plan G, are generally healthy, and prefer paying some cost-sharing rather than higher fixed premiums. But do the math—the premium savings often don't offset the cost-sharing exposure unless you're consistently healthy.

Plan G is, for most new Medicare beneficiaries (those eligible after 2020), the most comprehensive Medigap option available. The only thing it doesn't cover is the annual Part B deductible, which is $257 in 2026. Everything else—Part A deductible, Part B coinsurance, skilled nursing facility coinsurance, Part B excess charges, foreign travel emergency—covered.

### What 'Part B Excess Charges' Means

This benefit matters more than people realize. Some doctors opt to charge more than Medicare's approved amount—up to 15% more. This is called an excess charge. In most states, providers can bill you for this 15% above and beyond the standard 20% coinsurance.

If your surgeon charges $10,000 and Medicare approves $8,000, a non-participating provider can charge you an extra $1,200 (15% of $8,000). With Plan G, that's covered. Without this coverage (Plans A, B, D, K, L, M, N), you pay it.

Note: Some states have banned excess charges—Connecticut, Massachusetts, Minnesota, New York, Ohio, Pennsylvania, Rhode Island, and Vermont prohibit balance billing. If you're in one of those states, this benefit has less value.

### High-Deductible Plan G

There's also a High-Deductible Plan G (HDG) that has the same coverage as standard Plan G but requires you to pay a $2,870 deductible in 2026 before the plan pays anything. The premium for HDG is significantly lower—often $50–$80/month compared to $120–$220/month for standard Plan G.

This makes sense for someone who is genuinely healthy, wants catastrophic protection, and can comfortably handle the deductible if needed. Think of it like a high-deductible health plan for the working-age population—lower premium, higher first-dollar exposure.

### Plan G 2026 Premium Range

Premiums vary enormously by state, age, gender, tobacco use, and insurer. Some rough nationwide benchmarks for a 65-year-old nonsmoker:

By age 75, premiums for the same Plan G coverage typically run $200–$300/month nationally, with significant variation.

Plan N is currently the second most popular Medigap plan and it's gaining ground on Plan G, particularly among healthier, cost-conscious enrollees.

In exchange, Plan N premiums are meaningfully lower than Plan G—typically $30–$60/month less, depending on area and insurer.

### Plan G vs Plan N: The Math

| Factor | Plan G | Plan N | |---|---|---| | Typical monthly premium (age 65) | $130–$180 | $90–$130 | | Annual premium savings (vs G) | baseline | ~$400–$700/year | | Office visit copay | $0 | Up to $20 | | ER copay | $0 | Up to $50 | | Part B excess charges | Covered | Not covered | | Part B deductible | Not covered | Not covered |

### When Plan N Wins

If you see your primary care doctor 4 times a year and maybe 2 specialist visits—6 visits total—Plan N costs you at most $120/year in copays. If Plan N saves you $500/year in premiums over Plan G, you're ahead by $380.

If you see doctors frequently—12 or more office visits per year—the copays eat into those savings. At 15 visits with $20 copays, you've spent $300 in copays. Still probably ahead if premiums are $500 cheaper, but the margin narrows.

### When Plan G Is Better

### The Emergency Room Wild Card

The Plan N ER copay ($50) can sting if you go to the ER and aren't admitted. If you go to the ER three times and leave without admission, that's $150—a real cost. If you're admitted, the copay is waived. If your ER visits tend to result in admission (chronic heart condition, for example), Plan N's ER copay rarely applies.

The rest of the Medigap alphabet gets less attention for good reason—most people don't need them. But there are scenarios where they make sense.

### Plan A: The Baseline

Plan A is the most basic Medigap plan. It covers Part A coinsurance and hospital costs, Part B coinsurance or copay, blood, and Part A hospice coinsurance. That's it.

No Part A deductible coverage, no skilled nursing facility coinsurance, no foreign travel coverage. Plan A is cheaper than Plan G but leaves more exposure. For most people, it's not worth the trade-off—Plan G or N protection is worth the premium difference.

### Plan B

Adds coverage of the Part A deductible on top of Plan A. Decent but still missing skilled nursing, foreign travel, and excess charges coverage.

### Plan D

Adds skilled nursing facility coinsurance and foreign travel emergency coverage to Plan B's benefits. Still missing Part B excess charge coverage. Niche use case.

### Plan M

Covers 50% of the Part A deductible (unlike Plan G which covers 100%), plus skilled nursing, foreign travel. Part B deductible not covered. Lower premiums than Plan G. Makes sense if you're healthy and want some cost-sharing in exchange for lower premiums, but unlike Plan N, the copay structure here is on the Part A side (hospitalizations) rather than the Part B side (office visits).

### Plans K and L Revisited

If you want a cost-sharing structure and are comfortable with the math, Plan L at 75% coverage might hit a sweet spot. Premiums are meaningfully lower than Plan G, and the $3,610 OOP limit keeps your maximum exposure controlled. For someone in genuinely excellent health who sees a doctor maybe twice a year, Plan L or K can be a smart budget choice.

This is the most important timing information in all of Medicare Supplement shopping. Get this wrong and it costs you potentially thousands of dollars annually—forever.

### The Open Enrollment Period

During this 6-month window, every insurer selling Medigap in your state MUST sell you any Medigap plan they offer at their standard premium rate, regardless of your health history. Pre-existing conditions, past surgeries, chronic conditions—none of it matters. They can't charge you more for any of it.

This is called guaranteed issue.

Once this window closes, in most states, you can still buy Medigap, but insurers can ask about your health and deny you coverage, exclude pre-existing conditions for up to 6 months, or charge higher premiums based on your health.

### Why This Changes the Math

If you're 65 and in perfect health, any Medigap plan looks affordable. If you're 73 and have Type 2 diabetes, heart disease, and had a hip replacement, getting Plan G at a reasonable rate might be difficult or impossible in states without continuous enrollment protections.

This is why the conventional wisdom is: buy Medigap during your guaranteed issue period, even if you think you might want MA instead. The guaranteed issue right is worth capturing, and you can always compare MA vs. Medigap costs later, but getting that health underwriting clock ticking is the risk.

### Other Guaranteed Issue Situations

Beyond initial enrollment, there are specific triggering events that restore your guaranteed issue right:

The trial right is important. If you join Medicare Advantage during your IEP and drop it within 12 months to return to Original Medicare, you get a guaranteed issue right to buy Medigap Plans A, B, C, F, K, or L. This one-time right lets you try MA without permanently giving up your ability to get Medigap at standard rates.

Not all Medigap premiums work the same way. There are three pricing structures, and understanding them affects your long-term costs significantly.

### Community Rated (No-Age-Rated)

Everyone in the same area pays the same premium regardless of age. A 65-year-old and a 78-year-old pay the same amount. Premiums still increase over time due to inflation and claims experience, but they don't go up because you're aging.

This is the most consumer-friendly structure for long-term affordability. New York, Massachusetts, and Connecticut require community rating for all Medigap plans. If you live in one of these states, this is what you have.

### Issue-Age Rated

Your premium is based on your age when you first buy the policy—and it doesn't increase due to age. A 65-year-old pays less than a 70-year-old who buys the same plan. But once you lock in at 65, your premium doesn't go up just because you turn 70.

Premiums still increase over time due to inflation, but not due to your individual aging. Better long-term than attained-age, though still more expensive than community rated for older buyers.

### Attained-Age Rated

Your premium is based on your current age and goes up every year as you get older. This is the most common structure nationwide. At 65, premiums look very affordable. By 75, the same coverage costs meaningfully more. By 85, it can be dramatically more expensive.

The trap: people who bought an attained-age-rated Plan G at 65 for $130/month are sometimes paying $280–$350/month at 80. And they can't switch to a cheaper insurer without going through health underwriting, which they might fail.

### Which Pricing Method Is Better

For lifetime costs, community rated is generally best. Issue-age-rated is second. Attained-age is least favorable long-term but often cheapest at initial purchase. When comparing plans from multiple insurers, ask which pricing method they use—it's not always advertised prominently.

Because the benefits are standardized, comparing Medigap plans really is just comparing premiums and insurer quality. Here's the process.

### Get Quotes From Multiple Insurers for the Same Plan Letter

For a Plan G in any given zip code, you might find premiums ranging from $115/month to $220/month for identical coverage. That $105/month difference is $1,260/year—for the same exact benefits. This happens because insurers price independently and have different cost structures, risk pools, and marketing overhead.

Medicare.gov has a Medigap plan comparison tool. Your state's SHIP (State Health Insurance Assistance Program) can provide unbiased help comparing options. Private comparison sites like MedigapPros, SelectQuote, and GoHealth can show you multiple quotes simultaneously, though they're working on commission so understand their incentive structure.

### Compare at Least 5–6 Insurers

Serious names to get quotes from: AARP/UnitedHealthcare (largest by enrollment), Mutual of Omaha (strong in most states), Cigna, Humana, Aetna, Blue Cross Blue Shield (varies by state), and several strong regional players depending on your state.

### Look at Rate Increase History

A plan that's cheap today but has a history of aggressive annual premium increases isn't necessarily the best choice. Some state insurance departments publish historical rate increase data. Ask insurers directly about their rate increase history over the past 5 years. A 5–7% annual increase is roughly in line with medical inflation. 15–20% annual increases are a warning sign.

### Financial Stability Ratings

Medigap is long-term coverage. You want an insurer who will be around and solvent in 20 years. Check AM Best ratings—A or better is what you want. All of the major players have strong ratings, but smaller regional insurers vary.

### Discounts and Household Rules

Many Medigap insurers offer household discounts when two people in the same household are both enrolled with them—typically 5–12% off for both. If you and a spouse are both buying Medigap, buy from the same insurer and get the household discount.

Federal law sets the minimum framework for Medigap—the standardized plan letters, the open enrollment rights. But states can and do add consumer protections on top.

### States With Year-Round or Extended Open Enrollment

New York: Community rating + year-round open enrollment. You can buy any Medigap plan at any time regardless of health. This makes New York one of the most consumer-friendly Medigap markets in the country. The trade-off is higher premiums because the risk pool includes unhealthy buyers.

Massachusetts, Connecticut, Maine: Similar consumer-friendly rules with various year-round or extended open enrollment provisions.

Washington: Implemented a birthday rule—you have a 60-day window each year around your birthday to switch Medigap plans with relaxed underwriting requirements.

California, Oregon, Missouri, Louisiana, Idaho, Illinois: Also have birthday rules that give you annual switching rights.

### The Birthday Rule: A Hidden Opportunity

In states with birthday rules, you get an annual chance to switch Medigap insurers for the same plan letter or a plan with equal or lesser benefits, without full underwriting. This is valuable because it lets you shop for better rates every year without health consequences.

If you're in California and paying $250/month for Plan G from Insurer A, you can switch to Insurer B at $185/month during your birthday window. You don't have to explain your health history.

### States That Have Eliminated or Modified Standard Plans

Massachusetts and Minnesota have their own standardized plan structures that differ from the federal alphabet. If you're in those states, the plan names and coverages are different—work with a local SHIP or broker who knows the specifics.

### What This Means Practically

Before assuming anything about your Medigap options, look up your specific state's rules. Your state insurance commissioner's website usually has clear information. Or call your SHIP—every state has one, it's free, and they know the local rules cold.