This is the decision Open Enrollment actually forces, and it is usually presented as a cost comparison. It is not really a cost comparison. It is a trade between a cap and a choice, with a one-way door attached that most summaries leave out.
This applies to the United States. The comparison below is Medicare's own, and the 2027 projections come from CMS.
What Medicare itself says, side by side
| Original Medicare | Medicare Advantage | |
|---|---|---|
| Yearly out-of-pocket limit | No yearly limit on what you pay out of pocket, unless you have supplemental coverage | A yearly limit on what you pay for covered Medicare services |
| Doctors and hospitals | Any doctor or hospital that takes Medicare, anywhere in the US | May need to use providers in the plan's network |
| Prior authorization | In most cases, not needed | May be required before the plan covers certain services |
| Drug coverage | Join a separate Medicare drug plan (Part D) | Most plans include Part D, so no separate plan needed |
| Extra benefits | Does not cover routine physical exams, eye exams or most dental care | May offer extra benefits such as some vision, hearing and dental |
| Outside the US | Does not cover medical care outside the US | Does not cover medical care outside the US |
That table is the whole structural trade in one view: Medicare Advantage buys you a ceiling and sells you a network. Original Medicare buys you freedom and sells you an open-ended liability.
The first row is doing more work than it looks
"No yearly limit on what you pay out-of-pocket" is easy to read past. It means exactly what it says. In Original Medicare without supplemental coverage, a catastrophic year has no financial stop.
This is why Original Medicare is rarely held alone. It is normally held with a Medigap policy, which exists precisely to cover the share Original Medicare leaves you. The practical comparison is therefore not usually "Original Medicare vs Medicare Advantage" but "Original Medicare plus Medigap plus a Part D plan" vs "Medicare Advantage" — three premiums against one, buying a different shape of protection.
Compared that way, Medicare Advantage frequently costs less month to month. CMS projects the weighted average Medicare Advantage premium falling from $14.37 in 2026 to $12.00 in 2027. What that premium does not tell you is what a bad year costs, which depends on the plan's deductible, its copayments, its out-of-pocket limit, and whether the care you need is in network.
The part that is not reversible
Here is the asymmetry, and it is the most important thing on this page.
You can switch between Original Medicare and Medicare Advantage during Open Enrollment, in either direction. Medicare is clear, though, that it is illegal for anyone to sell you a Medigap policy while you are in a Medicare Advantage plan unless you are switching back to Original Medicare.
And the right to buy Medigap at standard rates, regardless of your health is not an annual right. It generally comes from a one-time six-month window that opens when you first enrol in Part B. Once that window closes, an insurer can in many cases refuse you, or price you on your health. The mechanics, and the handful of situations that reopen a guaranteed right, are in the guide to the six-month Medigap open enrolment window.
Read those two facts together and the shape of the decision changes:
- Choosing Medicare Advantage at 65 is easy to do and can be hard to undo, because the Medigap you would want on the way back may no longer be available to you at a price you would accept.
- Choosing Original Medicare plus Medigap at 65 is easy to undo, because moving into Medicare Advantage later is generally straightforward.
That is not an argument that one is correct. It is an argument that the two choices carry different amounts of future optionality, and that the cheaper monthly option is also the one with the narrower exit.
What is genuinely new for 2027
Two things worth factoring in this year specifically.
Average Medicare Advantage premiums are projected to fall. CMS puts the weighted average across all MA plans at $12.00 a month in 2027, down 16.5%, across roughly 5,532 plans, with projected enrolment of 34 million. The full set of 2027 figures, including the Part D out-of-pocket cap rising to $2,400, is in what CMS has published for 2027.
ACCESS is only available in Original Medicare. CMS's chronic care model, which began in July 2026 and adds tracks for heart failure, COPD, substance use disorder and tobacco cessation from 1 April 2027, is a model within Original Medicare. If you have one of those conditions, it is a genuine point in Original Medicare's favour that did not exist a year ago, and it is worth asking your clinician whether a participating organisation is available to you.
Who each one tends to suit
Not advice, and not a substitute for comparing actual plans. These are the patterns the structural differences produce.
Medicare Advantage tends to suit someone who is comfortable inside a network, whose doctors are already in it, who values a hard ceiling on annual costs, who wants dental and vision rolled in, and who does not expect to need highly specialised care from a particular out-of-network institution.
Original Medicare plus Medigap tends to suit someone who travels within the US and wants any provider to work, who has or expects a condition requiring specialist centres, who would find prior authorization an obstacle at a bad moment, or who places a high value on keeping the Medigap option open while they are still able to buy it.
The deciding question for most people is not cost. It is this: if you became seriously ill, would you want to be choosing the hospital, or would you want to be certain of the bill? Both are legitimate answers, and they point in opposite directions.
Five things to check before 7 December
- Are your current doctors in the plan's 2027 network? Check by name, for next year, not this year.
- What is the plan's out-of-pocket maximum? That number, not the premium, is what caps a bad year.
- Which of your drugs are on the formulary? Only covered drugs count toward the Part D cap, and the list of what else counts is shorter than most people expect.
- Is your Medigap window still open? If you are newly on Part B, this is the one decision with a deadline you cannot reopen.
- What does your Annual Notice of Change say? Supplemental benefits like the 2027 dental allowance are set per plan and move year to year, and the card a plan pays them onto now has federal rules of its own. The wider checklist is in what to check during Open Enrollment.
This article sets out the comparison Medicare publishes and the 2027 projections published by CMS. It is general information for a United States audience and is not insurance, medical, tax or financial advice. Plan terms, networks, formularies and costs vary enormously between individual plans and between states. Compare specific plans on Medicare Plan Finder and, for a decision this consequential, consider speaking to your State Health Insurance Assistance Program, which is free and not paid on a sale.
Sources
- Medicare.gov: Compare Original Medicare and Medicare Advantage (opens in a new tab)
- Medicare.gov: Understanding Medicare Advantage Plans (opens in a new tab)
- Medicare.gov: Choosing a Medigap Policy (opens in a new tab)
- CMS: Medicare Advantage and Medicare Prescription Drug Programs Expected to Remain Stable in 2027 (opens in a new tab)
- CMS Innovation Center: ACCESS Model (opens in a new tab)
- Medicare.gov: Parts of Medicare (opens in a new tab)
This article is general information for a United States audience and reflects the comparison published by Medicare and the 2027 projections published by CMS at the date of review. It is not insurance, medical, tax or financial advice, and it does not recommend any plan, insurer or course of action. Medicare Advantage plan terms, networks, formularies and out-of-pocket limits are set by individual plans, vary by state and change annually, and Medigap availability and pricing depend on your enrolment history and your state's rules. Confirm your own position on Medicare Plan Finder, with your State Health Insurance Assistance Program, or by calling 1-800-MEDICARE before changing coverage. Last reviewed 7 October 2026.
