Turning 65? Here's What You Need to Know About Medicare Supplement Plans
A step-by-step guide to understanding your options, enrollment deadlines, and how to choose the right Medigap plan.
What is a Medicare Supplement (Medigap) plan?
Original Medicare (Part A and Part B) covers most healthcare costs, but not all of them. You're still responsible for deductibles, coinsurance, and copays — the "gaps" in Medicare coverage.
A Medicare Supplement plan (also called Medigap) is private insurance that fills those gaps. It works alongside Original Medicare: Medicare pays its share first, then your Medigap plan covers some or all of the rest.
There are 10 standardized plans, each labeled with a letter (A, B, D, F, G, K, L, M, N). Every plan with the same letter covers the exact same benefits — the only difference between carriers is the price and customer service.
Your enrollment timeline
Timing matters. Your Medigap Open Enrollment Period gives you guaranteed-issue rights — don't miss it.
6 months before you turn 65
Sign up for Medicare Part A and Part B
You can enroll in Medicare up to 3 months before your 65th birthday. If you're already receiving Social Security, you may be enrolled automatically.
3 months before to 3 months after turning 65
Your Medigap Open Enrollment Period begins
This 6-month window starts the month you turn 65 AND are enrolled in Part B. During this period, insurance companies cannot deny you coverage or charge more because of health conditions.
During Open Enrollment
Compare plans and choose a carrier
All plans with the same letter cover the same benefits. Your decision comes down to which letter (coverage level) and which carrier (price and stability).
Before Open Enrollment closes
Enroll in your chosen plan
After your Open Enrollment Period ends, you may still be able to buy a Medigap policy, but the insurer can use medical underwriting — meaning they can charge more or deny coverage based on your health.
Which plan should you choose?
Most new enrollees choose Plan G or Plan N. Together, they account for over 80% of new Medigap enrollments.
Plan G
Covers everything except the Part B deductible ($283/year). Maximum predictability — you know exactly what you'll pay.
Best for: People who want peace of mind and minimal out-of-pocket costs.
Learn more about Plan GPlan N
Lower premiums than Plan G, with small copays ($20 office visits, $50 ER). Saves $30–60/month in most states.
Best for: Healthy people who rarely visit the doctor.
Learn more about Plan NCommon questions
What's the difference between Medicare Supplement and Medicare Advantage?
Medicare Supplement (Medigap) works with Original Medicare — it covers the gaps (deductibles, coinsurance, copays) that Medicare doesn't pay. Medicare Advantage (Part C) replaces Original Medicare with a private plan that bundles everything. Medigap gives you more freedom to see any doctor who accepts Medicare; Advantage plans usually have networks.
Do I need a Medicare Supplement plan?
Original Medicare covers about 80% of approved costs. Without supplemental coverage, you're responsible for the other 20% with no annual out-of-pocket cap. A single hospital stay could cost thousands. Most people choose either a Medigap plan or a Medicare Advantage plan to limit their exposure.
Can I change my Medigap plan later?
You can switch Medigap plans at any time, but outside of your Open Enrollment Period, the new insurer can use medical underwriting. This means they can charge more or deny coverage based on pre-existing conditions. That's why choosing the right plan during Open Enrollment is important.
Does Medigap cover prescription drugs?
No. Medigap plans don't cover prescription drugs. You'll need a separate Medicare Part D plan for drug coverage. You can enroll in Part D during the same enrollment period as your Medigap plan.
What does a Medigap plan cost?
Monthly premiums vary widely by plan letter, carrier, state, age, and gender. Plan N typically costs $80–180/month, and Plan G costs $100–250/month. The same plan from different carriers can vary by $100+/month in the same state — that's why comparison shopping matters.
Ready to see what plans cost in your state?
Enter your state and preferences — we'll show you the best options ranked by price, carrier strength, and rate stability.