Medicare Supplement insurance, also called Medigap, is a private policy that pays the costs Original Medicare leaves you owing: deductibles, coinsurance, and copays. In 2026, Medigap plans are standardized into lettered categories (A through N), so a Plan G policy covers the exact same benefits no matter which insurance company sells it. The main differences between insurers are price, customer service, and discounts. Monthly premiums for the most popular plan, Plan G, typically range from about $120 to $400 depending on age, ZIP code, and insurer. This guide breaks down what each plan covers, what it costs in 2026, and when you're allowed to enroll without being turned down for a health condition.
What Medigap Actually Covers
Original Medicare, meaning Part A (hospital) and Part B (medical), pays roughly 80% of most covered costs. It does not have an out-of-pocket maximum. Without supplemental coverage, a serious hospital stay or ongoing treatment can leave you owing thousands of dollars.
Medigap policies pay some or all of that remaining 20%, plus deductibles and coinsurance, depending on the plan letter you choose. Medigap does not work alongside Medicare Advantage. You either have Original Medicare plus a Medigap policy, or you have a Medicare Advantage plan, not both.
Medigap also does not cover prescription drugs. Anyone with a Medigap policy who wants drug coverage needs a separate stand-alone Part D plan.
2026 Medicare Cost Basics (What Medigap Is Filling In)
Understanding what Medigap covers starts with knowing what Original Medicare costs on its own in 2026:
| Medicare Cost | 2026 Amount |
|---|
| Part A inpatient hospital deductible (per benefit period) | $1,736 |
| Part A daily coinsurance, days 61 to 90 | $434/day |
| Part A daily coinsurance, lifetime reserve days | $868/day |
| Skilled nursing facility coinsurance, days 21 to 100 | $217/day |
| Part B annual deductible | $283 |
| Part B standard monthly premium | $202.90 |
| Part B coinsurance after deductible | 20% of Medicare-approved amount |
A Medigap policy is built to absorb some or all of these numbers, so a hospital stay that would otherwise cost you thousands out of pocket instead costs a flat monthly premium.
The 10 Standardized Medigap Plans
Federal law standardizes Medigap benefits across all insurers in every state except Massachusetts, Minnesota, and Wisconsin, which use their own standardized formats. Plans C and F are only available to people who became eligible for Medicare before January 1, 2020.
| Plan | Part A Coinsurance | Part B Deductible | Part B Excess Charges | Skilled Nursing Coinsurance | Foreign Travel Emergency |
|---|
| Plan A | Yes | No | No | No | No |
| Plan G | Yes | No | Yes | Yes | Yes (80%) |
| Plan N | Yes | No | No | Yes | Yes (80%) |
| High-Deductible Plan G | Yes | No | Yes | Yes | Yes (80%) |
| Plan F (pre-2020 only) | Yes | Yes | Yes | Yes | Yes (80%) |
Plan G is the most comprehensive option available to anyone newly eligible for Medicare, covering everything except the annual Part B deductible ($283 in 2026). Plan N costs less but requires small copays: up to $20 for a doctor visit and up to $50 for an ER visit that doesn't result in admission, and it does not cover Part B excess charges (the extra amount some doctors can legally bill above the Medicare-approved rate).
2026 Monthly Premium Estimates
Medigap premiums vary by age, gender, tobacco use, ZIP code, and insurer, so shop multiple carriers before choosing one.
| Plan | Typical 2026 Monthly Premium Range |
|---|
| Plan G | $120 to $400 |
| Plan N | $95 to $350 |
| High-Deductible Plan G | $40 to $90 |
| Plan A | $80 to $200 |
High-Deductible Plan G carries a 2026 deductible of $2,950. You pay all Medicare-covered costs out of pocket until you hit that amount, then the plan covers the rest of standard Plan G's benefits for the remainder of the year. It's a lower-premium option for people who want protection from a catastrophic bill but don't need first-dollar coverage.
Plan N typically saves $20 to $50 a month compared to Plan G, or roughly $240 to $600 a year, in exchange for the small copays and no excess-charge coverage.
When to Enroll: The 6-Month Window That Matters Most
Timing is the single most important decision in buying a Medigap policy.
You get a one-time, 6-month Medigap Open Enrollment Period that starts the month you're both 65 or older and enrolled in Medicare Part B. During this window:
- Insurers must sell you any policy they offer, regardless of your health history
- You cannot be charged more or denied coverage because of pre-existing conditions
- You can pick any insurer selling in your state based purely on price and service
This window does not repeat. Once it closes, insurers in most states can use medical underwriting, meaning they can charge you more, add waiting periods for pre-existing conditions, or deny you a policy outright based on your health.
Outside the open enrollment window, federal law still guarantees issue rights in specific situations, most commonly if you lose employer coverage, your Medicare Advantage plan leaves the area, or your insurer becomes insolvent. In those cases you typically have 63 days from the date your coverage ends to buy a Medigap policy with guaranteed issue protections.
A small number of states (including California, New York, and Connecticut) offer additional year-round or annual guaranteed-issue protections beyond the federal minimum, so check your state's rules before assuming you've missed your window.
Medigap vs. Medicare Advantage
These are the two competing paths for covering Original Medicare's gaps, and they work very differently.
| Feature | Medigap | Medicare Advantage |
|---|
| Monthly premium | Higher (plus Part B premium) | Often $0, plus Part B premium |
| Network restrictions | None, any doctor accepting Medicare | Usually HMO/PPO network |
| Out-of-pocket costs | Low, predictable | Copays and coinsurance vary by plan |
| Extra benefits (dental, vision) | Not included | Often included |
| Prescription drug coverage | Separate Part D plan needed | Usually bundled in |
| Switching later | Health underwriting may apply | Annual enrollment window |
People who travel frequently, want to keep any doctor nationwide, or want predictable costs tend to prefer Medigap. People focused on lower monthly premiums and bundled extras like dental and vision tend to prefer Medicare Advantage.
How to Apply for a Medigap Policy
- Confirm you're enrolled in Medicare Part A and Part B. You cannot buy Medigap without both.
- Identify your open enrollment window. Mark the date your Part B started; your 6-month clock begins then.
- Compare plan letters, not just companies. Since benefits are standardized, focus your comparison on premium, insurer financial strength, and customer reviews.
- Get quotes from at least 3 to 5 insurers for the same plan letter, since prices for identical coverage can vary by hundreds of dollars a year.
- Apply directly with the insurer or through a licensed agent. There's no dedicated "Medigap enrollment" portal on Medicare.gov, applications go through private insurance companies.
- Keep your existing coverage active until your new Medigap policy is confirmed and in force, to avoid a coverage gap.
Frequently Asked Questions
What is the difference between Medigap and Medicare Advantage?
Medigap is a supplement that works alongside Original Medicare (Parts A and B) to pay the gaps in coverage, with no provider network restrictions. Medicare Advantage is a private plan that replaces Original Medicare entirely, typically with a network, lower premiums, and bundled extra benefits like dental and vision.
What is the best Medigap plan for 2026?
Plan G is generally considered the best value for comprehensive coverage among people newly eligible for Medicare, since it covers everything except the $283 Part B deductible. Plan N is a strong lower-cost alternative for people willing to pay small copays in exchange for a lower monthly premium.
Can I be denied a Medigap policy?
Yes, outside your guaranteed issue windows. During your initial 6-month Medigap Open Enrollment Period, or during a federally protected guaranteed issue event, insurers cannot deny you or charge more based on health. Outside those windows, insurers in most states can use medical underwriting to deny coverage or increase your premium.
How much does Medicare Supplement insurance cost in 2026?
Costs vary widely by plan, age, and location. Plan G typically runs $120 to $400 a month, and Plan N typically runs $95 to $350 a month. You'll also continue paying your Part B premium, which is $202.90 a month in 2026 for most people.
Does Medigap cover prescription drugs?
No. Medigap policies do not include prescription drug coverage. You need a separate stand-alone Medicare Part D plan for medications, whether or not you have a Medigap policy.
Can I switch Medigap plans later?
Yes, but after your initial open enrollment window closes, switching usually requires passing medical underwriting unless you qualify for a guaranteed issue right. Some insurers offer "free look" periods of 30 days when you first switch, letting you test a new policy while keeping your old one temporarily.
Do all Medigap plans cost the same for the same letter?
No. While the benefits for a given plan letter (like Plan G) are identical across insurers, premiums for that same coverage can vary by hundreds of dollars a year depending on the company, so it pays to compare multiple quotes before enrolling.
