Original Medicare is excellent coverage — but it has one serious flaw: there is no out-of-pocket maximum. Without supplemental coverage, a major illness or extended hospital stay could cost you tens of thousands of dollars in coinsurance, deductibles, and copays.
That's exactly what Medigap (Medicare Supplement Insurance) is designed to solve. A Medigap plan wraps around your Original Medicare coverage and pays most or all of the costs that Medicare leaves behind. For many seniors, it's the single most important insurance decision they'll make after turning 65.
Medigap is private health insurance that supplements Original Medicare (Parts A and B). It does NOT work with Medicare Advantage plans. To use Medigap, you must be enrolled in Medicare Parts A and B.
How Medigap Works
When you have a medical expense, Medicare pays its share first (typically 80% of approved costs for Part B services). Your Medigap plan then pays some or all of the remaining 20%, plus other costs like deductibles and excess charges.
Medigap plans are sold by private insurance companies, but the benefits of each plan are standardized by the federal government. This means a Plan G from Company A covers the exact same benefits as a Plan G from Company B — the only difference is the premium you pay.
All 10 Medigap Plans — Side by Side
There are 10 standardized Medigap plans, labeled A through N. Here's what each one covers:
| Benefit | A | B | D | G ⭐ | G-HD | N ⭐ | K | L | M | C* |
|---|---|---|---|---|---|---|---|---|---|---|
| Part A coinsurance & hospital costs | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ | ✅ |
| Part B coinsurance or copayment | ✅ | ✅ | ✅ | ✅ | ✅ | ✅* | 50% | 75% | ✅ | ✅ |
| Part A deductible | ❌ | ✅ | ✅ | ✅ | ✅ | ✅ | 50% | 75% | 50% | ✅ |
| Part B deductible ($257/yr) | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ❌ | ✅ |
| Part B excess charges | ❌ | ❌ | ❌ | ✅ | ✅ | ❌ | ❌ | ❌ | ❌ | ❌ |
| Foreign travel emergency (80%) | ❌ | ❌ | ✅ | ✅ | ✅ | ❌ | ❌ | ❌ | ✅ | ✅ |
*Plan N: $20 copay for office visits, $50 for ER. *Plan C: only available to those eligible before Jan 1, 2020.
The 3 Plans Most Seniors Should Consider
Plan G — Best Overall (Most Popular)
Plan G is the most comprehensive Medigap plan available to new Medicare enrollees today. It covers virtually everything except the Part B annual deductible ($257 in 2026). Once you meet that small deductible, you pay absolutely nothing for any Medicare-approved service for the rest of the year — no copays, no coinsurance, no limits.
Plan G is ideal if you: use medical care frequently, want total cost predictability, travel internationally, or simply want zero financial surprises.
John, 65, in Ohio pays $142/month for Plan G. In a year where he has knee surgery, 4 specialist visits, and physical therapy — his total out-of-pocket is $257 (just the Part B deductible). Without Medigap, he would have owed over $4,800.
Plan N — Best Value (Lower Premium)
Plan N covers everything Plan G covers, except Part B excess charges. You also pay a $20 copay for office visits and $50 for emergency room visits (waived if admitted). In return, premiums are typically 15–25% lower than Plan G.
Plan N is ideal if you: are relatively healthy, have a good primary care doctor who accepts Medicare assignment (meaning no excess charges), and want to save on monthly premiums.
Plan G High-Deductible (G-HD) — Best for Healthy Seniors
Same coverage as Plan G, but you pay a high deductible ($2,870 in 2026) before the plan kicks in. In exchange, premiums are dramatically lower — often $40–$70/month. If you rarely use healthcare, you'll save money overall. Think of it as catastrophic coverage with low premiums.
The Best Time to Buy Medigap — Don't Miss This Window
Timing your Medigap purchase is critical. Your Medigap Open Enrollment Period begins the month you turn 65 AND are enrolled in Medicare Part B. This 6-month window is the only time insurers are legally required to sell you any Medigap plan at the best available rate — regardless of your health conditions.
After your 6-month open enrollment window closes, insurers in most states can reject your application or charge higher premiums based on pre-existing conditions. This is the #1 Medigap mistake seniors make — waiting too long and then being unable to get coverage or being charged dramatically more.
What Determines Your Medigap Premium
All Plan G policies cover the same benefits — but premiums vary widely between insurers and states. Three pricing methods are used:
- Community-rated: Everyone pays the same premium regardless of age. Best long-term value — your premium only rises with inflation, not your age.
- Issue-age-rated: Premium is based on your age when you buy. Stays relatively stable over time.
- Attained-age-rated: Premium starts low but increases as you age. Cheapest at 65, most expensive by 80+. Most common — be careful.
Always ask an insurer which pricing method they use before buying. An attained-age plan that's $30/month cheaper at 65 can easily cost $200/month more by age 78.
How to Compare Medigap Plans and Prices
- Use Medicare's official plan finder at medicare.gov/medigap-supplemental-insurance-plans — lists all insurers in your state with current premiums
- Get quotes from at least 3 different insurers for the same plan letter — premiums for identical coverage can differ by $50–$150/month
- Check the insurer's financial stability rating (A.M. Best or Moody's) — you want a company that will be around for decades
- Ask about household discounts — many insurers offer 5–12% off if two people in the same household both buy policies
- Call your State Health Insurance Assistance Program (SHIP) for free, unbiased help comparing plans — find yours at shiphelp.org