Original Medicare covers a lot — but it doesn't cover everything. Medicare Supplement insurance, also known as Medigap, fills the gaps left by Original Medicare, including deductibles, copayments, and coinsurance. Here's what you need to know to choose the right plan.
What Is Medicare Supplement Insurance?
Medicare Supplement (Medigap) insurance is private health insurance that helps pay some of the costs that Original Medicare (Parts A and B) doesn't cover. These "gaps" include the Part A hospital deductible ($1,676 per benefit period), Part B coinsurance (20% of most outpatient services), and skilled nursing facility coinsurance.
Medigap plans are standardized by the federal government and sold by private insurance companies. Each plan type is labeled by a letter (Plan A, Plan G, Plan N, etc.) and covers the same standardized benefits regardless of which insurer sells it — so you can compare based on price and company reputation.
Most Popular Medigap Plans in 2026
| Plan | Part A Deductible | Part B Coinsurance | Part B Deductible | Foreign Travel |
|---|---|---|---|---|
| Plan G | Covered | Covered | Not covered | 80% (after deductible) |
| Plan N | Covered | Covered* | Not covered | 80% (after deductible) |
| Plan A | Not covered | Covered | Not covered | Not covered |
| Plan K | 50% covered | 50% covered | Not covered | Not covered |
*Plan N has copays up to $20 for office visits and $50 for ER visits not resulting in inpatient admission.
Plan G vs. Plan N: What's the Difference?
Plan G is the most comprehensive Medigap plan available to new Medicare enrollees. It covers nearly all Medicare gaps except the annual Part B deductible ($257 in 2026). Once you meet the deductible, Plan G covers 100% of your Part B coinsurance — giving you predictable, low out-of-pocket costs.
Plan N is the second most popular option. It covers Part B coinsurance with the exception of small copays ($20 for doctor visits, $50 for ER). Plan N typically has lower premiums than Plan G — making it a good fit if you don't visit the doctor frequently.
When to Enroll in Medicare Supplement
The best time to enroll is during your Medigap Open Enrollment Period — the 6-month window that starts the first month you are both age 65+ and enrolled in Medicare Part B. During this window, insurers must sell you any Medigap plan at the same price as a healthy applicant, regardless of your health history.
After this window closes, you may face medical underwriting — meaning insurers can charge you more or deny coverage based on pre-existing conditions (except in states with additional protections).
How Much Does Medicare Supplement Cost?
Medigap premiums vary by plan type, insurer, your age, gender, tobacco use, and location. Plan G premiums for a 65-year-old woman typically range from $90 to $180 per month. Plan N premiums are often 15–30% lower. Premiums generally increase with age.
There are three premium rating methods insurers use:
- Community-rated: Same premium for everyone regardless of age — premiums still increase over time.
- Issue-age rated: Premium based on age when you first bought the policy — may be lower long-term.
- Attained-age rated: Premium increases as you age — starts low but rises.
Medicare Supplement vs. Medicare Advantage
Both are ways to add coverage beyond Original Medicare, but they work very differently:
- Medicare Supplement works with Original Medicare. You can see any Medicare-accepting doctor nationwide, with very low out-of-pocket costs after your deductible.
- Medicare Advantage replaces Original Medicare with a private plan. Advantage plans often include extra benefits (dental, vision, OTC) and have lower premiums — but use provider networks and have more out-of-pocket exposure.
For people who want predictable costs and access to any doctor in the country, Medigap is usually the better choice. For those who want extra benefits at a lower premium and are comfortable using a network, Medicare Advantage may be the right fit.
How to Choose a Medigap Plan
The right plan depends on your health, how often you use medical services, your budget, and whether you travel. A licensed Medicare advisor can compare prices from multiple insurers in your area and help you choose the right plan for your needs.
Call 1-866-340-3441 to get a free, no-obligation Medicare Supplement comparison from Senior Benefit Assistance.