Medicare Advantage and Medigap often get compared as if they’re two competing products solving the same problem. They aren’t. Medicare Advantage is a replacement for how Original Medicare is delivered. Medigap is a supplement that works alongside Original Medicare. Understanding that distinction is the key to this whole decision, because it means the real choice isn’t “Medicare Advantage or Medigap.” It’s “Medicare Advantage, or Original Medicare plus Medigap.”
This guide focuses specifically on how Medigap works as a product, what it actually covers, and how it stacks up against Medicare Advantage’s cost structure. For the fuller comparison of Medicare Advantage against Original Medicare more broadly, see Senioridy’s Medicare Advantage vs. Original Medicare guide.
The Core Difference: Replacement vs. Supplement
- Medicare Advantage (Part C) is offered by private insurers and replaces Original Medicare entirely. The insurer manages the benefit, typically through an HMO or PPO network, and usually bundles in Part D drug coverage and extras like dental and vision.
- Medigap (Medicare Supplement Insurance) doesn’t replace anything. It’s a separate policy purchased alongside Original Medicare that pays some or all of the deductibles, copays, and coinsurance Original Medicare leaves to the patient.
These two cannot be combined. A person enrolled in Medicare Advantage cannot also buy a Medigap policy. Choosing Medicare Advantage means relying entirely on that plan’s built-in cost structure. Choosing Original Medicare plus Medigap means paying for two separate things (the Part B premium and a Medigap premium) in exchange for far more predictable costs and no provider network.
What Medigap Actually Covers
Medigap policies are standardized by letter (A through N) under federal law. A given letter offers identical core benefits no matter which insurance company sells it; price and customer service are the only real differences between carriers selling the same letter. Two letters dominate the market for people newly eligible for Medicare since 2020:
Plan G: The Comprehensive Option
Plan G covers nearly everything Original Medicare leaves unpaid, with one exception: the annual Part B deductible ($283 in 2026). Once that deductible is met for the year, Plan G covers the rest, including Part A and Part B coinsurance, the Part A hospital deductible, skilled nursing facility coinsurance, and Part B excess charges (the amount some providers are legally allowed to bill above Medicare’s approved rate). For someone who wants to never think about a medical bill again beyond that one deductible, Plan G is the closest thing to that outcome currently available to new enrollees.
Plan N: Lower Premium, Small Trade-Offs
Plan N covers the same broad categories as Plan G but at a meaningfully lower monthly premium, commonly $40 to $60 less per month. The trade-off is two gaps: Plan N doesn’t cover Part B excess charges, and it requires small copays, up to $20 for an office visit and up to $50 for an emergency room visit that doesn’t result in admission. For someone in good health who doesn’t see specialists frequently and whose doctors accept Medicare’s approved rates without billing extra, Plan N’s lower premium often works out to genuine savings over the year.
A simple way to think about the choice between the two: Plan G trades a higher monthly premium for cost certainty at the point of care. Plan N trades a small amount of that certainty for a lower premium every month. Neither is a wrong answer; the right one depends on expected utilization.
Cost Comparison: A 2026 Snapshot
- Medicare Advantage: often a $0 to low monthly plan premium on top of the standard Part B premium ($202.90 in 2026), with copays and coinsurance at the time of each service, capped at an annual out-of-pocket maximum of $9,250 for in-network care at the federal limit (the average MA enrollee’s plan limit is considerably lower, roughly $5,400).
- Original Medicare + Medigap Plan G: the Part B premium, plus a Medigap premium commonly in the $130 to $220+ monthly range depending on age, state, and insurer, plus the $283 annual Part B deductible. After that deductible, costs for Medicare-covered services are essentially fully covered for the rest of the year.
- Original Medicare + Medigap Plan N: similar structure to Plan G, but with a lower monthly premium (commonly $40 to $60 less than Plan G) offset by small per-visit copays.
The honest answer to which costs less in a given year is: it depends entirely on how much care gets used. A healthy person with few medical needs may genuinely spend less on Medicare Advantage’s low premium. Someone managing a chronic condition, a serious diagnosis, or simply a year with an unplanned hospitalization may find that Medigap’s predictable costs, despite the higher monthly premium, save real money and remove a lot of financial uncertainty. Senioridy’s Medicare Advantage Costs Explained guide walks through MA’s cost structure, including the out-of-pocket maximum, in more depth.
What Neither Option Covers
It’s worth being clear about the limits that apply regardless of which path is chosen. Neither Medicare Advantage nor Medigap covers long-term custodial care, the kind of help with bathing, dressing, and daily activities that doesn’t require a skilled medical professional. Medigap specifically does not include prescription drug coverage at all; a separate standalone Part D plan is required alongside it. Routine dental, vision, and hearing care also generally fall outside both Original Medicare and Medigap, though many Medicare Advantage plans include some coverage for these as supplemental benefits.
Provider Access: The Other Major Difference
Beyond cost, the other defining difference is provider access. Original Medicare with Medigap allows a person to see any doctor or hospital in the country that accepts Medicare, with no referrals and no network restrictions. Medicare Advantage generally limits coverage to the plan’s network, with HMO plans typically requiring a primary care referral for specialists and PPO plans allowing out-of-network care at a higher cost. For families who travel frequently, split time between states, or want unrestricted access to a specific specialist or academic medical center, this difference can matter as much as the cost comparison.
The Timing Decision That Matters More Than the Cost Comparison
Here’s the detail that catches the most people off guard, and it’s worth understanding even before running the numbers above. Medigap is not guaranteed to be available whenever someone wants it. Federal law guarantees Medigap enrollment without medical underwriting only during specific windows, most importantly the six-month period starting when a person first enrolls in Part B at 65 or older. Outside that window, in most states, a Medigap insurer can review medical history and charge more, impose a waiting period, or deny coverage entirely.
This matters enormously for the Medicare Advantage vs. Medigap decision because it makes the two paths asymmetrical. Choosing Original Medicare with Medigap now and switching to Medicare Advantage later is straightforward. Choosing Medicare Advantage now and trying to add Medigap later, say, after a new diagnosis prompts the idea, may not be possible at standard rates, or at all, depending on the state and the specific circumstances. A companion Senioridy guide covers this timing trap, guaranteed issue rights, and the exact mechanics of switching back to Original Medicare in full detail.
A Practical Way to Decide
- Lean toward Medicare Advantage when: overall health is good, specialist needs are limited, the plan’s network includes preferred providers, and the lower monthly premium and extra benefits (dental, vision, hearing) hold real value.
- Lean toward Original Medicare + Medigap when: managing a chronic or complex condition, frequent specialist or hospital care is likely, traveling or splitting time between states matters, or predictable monthly costs are worth paying more for upfront.
- Weigh the timing risk either way: a person who is healthy now but has reason to expect future care needs, family history, a developing condition, may want to factor in that Medigap’s best-priced, guaranteed availability is now, not necessarily later.
This decision benefits from a second opinion that isn’t trying to sell anything. A SHIP counselor provides free, unbiased Medicare guidance in every state and can walk through both the cost comparison and the timing considerations for an individual’s specific health situation. Medicare’s own Plan Finder tool can also show what specific Medigap policies and Medicare Advantage plans actually cost in a given ZIP code.
Find Senior Care Support Near You
Whatever Medicare path a family chooses, having the right care providers in place matters just as much as understanding the coverage. Search Senioridy’s in-home senior care directory or skilled nursing facility directory to find providers in your area.
This article is for informational purposes only and does not constitute legal, financial, or medical advice. Medicare Advantage and Medigap rules, costs, and availability are set by CMS and individual insurers and are subject to change, and vary by state. For free, personalized guidance on your specific situation, contact your State Health Insurance Assistance Program (SHIP) counselor at shiphelp.org, available in every state at no cost.