Look, Medicare is confusing. It’s designed by the government. We can’t make it simple, but we can make it clearer. And one of the most important things to understand about Medicare is what it doesn’t cover — because those gaps are where Medigap comes in.
Original Medicare pays 80% of most approved medical costs. That sounds pretty good until you realize there’s no annual cap on your 20%. A serious hospitalization, a cancer diagnosis, a major surgery — that 20% can add up to tens of thousands of dollars. Medigap (also called Medicare Supplement Insurance) is private insurance that picks up those leftover costs.
We spent weeks researching every Medigap plan letter, pulling premium data from dozens of carriers, and talking to SHIP counselors to put this guide together. The part that confuses people most is the alphabet soup of plan options — A through N, each covering different things. But here’s the good news: Plans G and N are what most people actually need, and we’ll explain exactly why below.
Our team member David Chen helped both his parents enroll in Medigap Plan G when they turned 65, and it was one of the better financial decisions they’ve made. His dad had a knee replacement last year, and their total out-of-pocket cost beyond the monthly premium was $257 — the Part B deductible. Everything else was covered.
One important note: Medicare premiums, deductibles, and plan costs get updated by CMS every year. We keep this page current, but always double-check at medicare.gov or call your state’s SHIP program (free, unbiased counseling). Want to talk it through? Email hello@seniorslist.com — real people, real answers.
Quick answer: Medigap fills the gaps in Original Medicare — covering deductibles, copays, and coinsurance that Medicare doesn’t. Plan G is the best choice for most new enrollees (covers nearly everything except the Part B deductible). Plan N is the best value if you’re healthy and don’t mind small copays. Enroll during your 6-month Open Enrollment Period starting at age 65 — miss it and you may face higher rates or denial.
What Is Medigap? A Complete Guide
Original Medicare covers a lot — but not everything. Beneficiaries can face significant out-of-pocket costs from deductibles, copayments, and coinsurance. Medigap, also called Medicare Supplement Insurance, is designed to fill those financial gaps.
How Medigap Works
When you have a medical expense, Original Medicare pays its share first. Then your Medigap policy pays its portion of the remaining cost. The result is dramatically reduced — or often eliminated — out-of-pocket expenses.
You pay a monthly premium for Medigap in addition to your Medicare Part B premium. In exchange, the Medigap plan handles costs that Medicare leaves behind.
Important: Medigap works exclusively with Original Medicare (Parts A and B). It cannot supplement Medicare Advantage.
The Medigap Plans: A through N
Medigap plans are standardized by the federal government. Every insurer must offer the same benefits for each plan letter — so Plan G from Humana covers the exact same services as Plan G from Mutual of Omaha. The only difference between carriers is the premium they charge.
The table below shows what each plan covers. Most new enrollees only need to focus on Plans G and N — the rest are either discontinued (F, C) or serve niche needs.
| Benefit | A | B | D | G | K | L | M | N |
|---|---|---|---|---|---|---|---|---|
| Part A coinsurance + hospital days | Yes | Yes | Yes | Yes | Yes | Yes | Yes | Yes |
| Part B coinsurance/copay | Yes | Yes | Yes | Yes | 50% | 75% | Yes | Yes* |
| Blood (first 3 pints) | Yes | Yes | Yes | Yes | 50% | 75% | Yes | Yes |
| Part A hospice coinsurance | Yes | Yes | Yes | Yes | 50% | 75% | Yes | Yes |
| Skilled nursing facility coinsurance | No | No | Yes | Yes | 50% | 75% | Yes | Yes |
| Part A deductible | No | Yes | Yes | Yes | 50% | 75% | 50% | Yes |
| Part B deductible | No | No | No | No | No | No | No | No |
| Part B excess charges | No | No | No | Yes | No | No | No | No |
| Foreign travel (80%) | No | No | Yes | Yes | No | No | Yes | Yes |
*Plan N requires copays of up to $20 for office visits and $50 for ER visits that don’t result in admission.
Plan F (no longer available to new enrollees after Jan 1, 2020) and Plan C (also discontinued for new enrollees) covered all benefits including the Part B deductible. Beneficiaries who became Medicare-eligible before 2020 can still purchase these plans.
Most Popular Plans for New Enrollees
Plan G — Most Popular
Plan G is the most comprehensive plan available to new Medicare beneficiaries. It covers everything except the Part B deductible ($257 in 2026). Once you pay that deductible, your out-of-pocket costs are essentially zero for Medicare-approved services.
Best for: Seniors who want maximum coverage and predictable costs.
Plan N — Best Value
Plan N offers strong coverage at lower premiums than Plan G. The trade-off: you pay copays of up to $20 for some doctor office visits and up to $50 for ER visits that don’t result in admission.
Best for: Seniors who are generally healthy and comfortable with modest visit copays.
Plan K and Plan L — Cost-Sharing Plans
These plans have the lowest premiums but require you to share a portion of costs (50% for Plan K, 25% for Plan L) until you reach an out-of-pocket maximum. Once reached, the plan covers 100%.
Best for: Seniors who want protection against catastrophic costs but can manage moderate expenses.
How Medigap Is Priced
Insurance companies use one of three pricing models for Medigap:
Community-Rated
Everyone in the same geographic area pays the same premium regardless of age. Premiums rise due to inflation and healthcare costs, but not because of your age alone.
Best for: Seniors who plan to keep the policy long-term — you won’t pay more as you age.
Issue-Age Rated
Your premium is locked in at the rate for your age when you first buy the policy. Premiums won’t rise due to aging but can increase due to inflation.
Best for: Younger Medicare enrollees who want to lock in a lower rate.
Attained-Age Rated
The most common pricing model. Premiums start lower but increase as you get older. What looks affordable at 65 may become expensive at 80.
Caution: These plans appear cheapest initially but tend to cost the most over a lifetime.
When to Enroll in Medigap
Open Enrollment Period
The six months beginning with the month you turn 65 and enroll in Medicare Part B is your Open Enrollment Period (OEP). During this window:
- Insurance companies must accept your application regardless of health conditions
- They cannot charge higher premiums due to pre-existing conditions
- You have access to all plans sold in your state
Missing the OEP means companies can medically underwrite your application — potentially denying coverage or charging higher rates.
Guaranteed Issue Rights
Certain situations give you guaranteed access to Medigap outside the OEP:
- Your Medicare Advantage plan is leaving your area
- You’re within the first 12 months of a Medicare Advantage plan (Trial Right)
- Your Medigap insurer goes bankrupt
Trial Right
If you enroll in Medicare Advantage for the first time after leaving Original Medicare + Medigap, you have 12 months to return to Original Medicare and buy any Medigap policy without medical underwriting.
Medigap vs. Medicare Advantage: Which Is Better?
| Factor | Medigap | Medicare Advantage |
|---|---|---|
| Monthly cost | Higher ($100–$300+ for Medigap) | Often $0 premium |
| Network restrictions | None (any Medicare provider) | Usually in-network only |
| Extra benefits (dental, vision) | No | Usually included |
| Out-of-pocket maximum | Near zero with comprehensive plans | $9,350 or less (2026) |
| Best for | Frequent care users; travelers | Healthy seniors who want extras |
There is no universally right answer. Heavy users of medical services often come out ahead with Medigap’s comprehensive coverage. Healthier seniors may prefer Medicare Advantage’s $0 premiums and extra benefits.
Finding the Best Medigap Rate
Since all carriers offer identical coverage for each plan letter, comparing prices is straightforward. Get quotes from multiple carriers and compare:
- Current premium for your age and location
- Pricing method (community, issue-age, or attained-age)
- Financial strength rating (look for AM Best “A” or better)
- Discounts for spouses enrolled together or automatic payment
SeniorsList recommends getting at least three quotes before selecting a Medigap plan.
Note: Medicare premiums, deductibles, and cost-sharing amounts change annually. Always verify current figures at medicare.gov before making enrollment decisions.