Medicare open enrollment 2027, explained
Original Medicare with a Medigap policy, Medicare Advantage and Part D drug plans in plain words, and what the fall window lets you change. No plan recommendations.
Explain it like I'm 5
Medicare is like choosing how to get around town and how to pay for medicine. Original Medicare lets you use any doctor or hospital that accepts Medicare, while Medicare Advantage uses a private plan with its own rules. From October 15 through December 7, 2026, you can change health or drug coverage for January 1, 2027. If you already have Medicare Advantage, you also have a separate January 1 through March 31, 2027 period to make one change.
This explains. It does not advise.
Where all four AIs agree is the solid ground. Where they disagree is exactly what to ask a licensed insurance agent or a SHIP counselor. This guide never names or recommends a plan.
Your options
Not good versus bad: each one fits some people and costs others.
Original Medicare with a Medigap policy
Original Medicare includes Part A, hospital insurance, and Part B, medical insurance for doctors and outpatient care. A Medigap policy is private insurance that helps pay some costs left by Original Medicare.
Fits you if
- you want to use doctors and hospitals nationwide that accept Medicare
- you travel or live in more than one place during the year
- you want separate choices for medical and drug coverage
Watch out for
- Medigap has a separate monthly premium, and 2027 amounts are not published yet
- Buying Medigap later can cost more or be unavailable, depending on health and state rules
- You cannot use Medigap with Medicare Advantage
Medicare Advantage
Medicare Advantage, also called Part C, is a private plan that provides your Part A and Part B benefits instead of Original Medicare. Most plans include Part D drug coverage, but networks, costs, referrals, approvals, and extra benefits differ. You usually use the plan's network for non-emergency care.
Fits you if
- you want medical and usually drug coverage bundled into one plan
- your doctors, hospitals, and medicines are covered by the plan you are considering
- you are comfortable following the plan's network and approval rules
Watch out for
- Provider networks, drug lists, costs, and rules can change each year
- Returning to Original Medicare may not guarantee access to Medigap later
A Part D drug plan
A stand-alone Part D plan adds prescription drug coverage to Original Medicare. Each plan has a drug list, called a formulary, plus its own pharmacies, costs, and coverage rules. Review it every year because your drugs, pharmacy choices, costs, and plan rules can change for 2027.
Fits you if
- you have Original Medicare and want prescription drug coverage
- your exact medicines, doses, pharmacies, and expected costs match the plan
- you want to choose drug coverage separately from medical coverage
Watch out for
- Skipping Part D without other creditable drug coverage can cause a late enrollment penalty later
Numbers to know
- 2027 Part D out-of-pocket cap
- $2,400 under the standard benefit (CMS calls it the out-of-pocket threshold). It was $2,100 in 2026.
- CMS, CY 2027 Medicare Advantage and Part D Rate Announcement, Table V-2checked November 3, 2026
- 2027 Part D deductible, highest allowed
- $700 under the standard benefit. It was $615 in 2026.
- CMS, CY 2027 Medicare Advantage and Part D Rate Announcement, Table V-2checked November 3, 2026
The questions that decide it
- Do my doctors, hospitals, and preferred pharmacies accept or participate in this coverage?
- Are every one of my medicines, doses, pharmacies, and coverage rules checked for 2027?
- Would I rather pay separate premiums for broader choice or follow one plan's network?
- Do I travel or live outside my plan's service area during the year?
- If I leave Medicare Advantage, can I buy Medigap under my state's rules?
Common mistakes
- Assuming your current plan stays unchanged, because costs, networks, drug lists, and benefits can change for 2027.
- Choosing only by monthly premium, while ignoring costs when you receive care or fill prescriptions.
- Leaving Medicare Advantage without checking Medigap rights, since later purchase may involve health questions or higher costs.
- Missing December 7, 2026, which can delay a desired January 1 coverage change.
- Going without creditable drug coverage because you take few medicines, which can lead to a later penalty.
Questions to ask a professional
Ask a licensed insurance agent or a SHIP counselor.
- Which 2027 options cover my exact doctors, hospitals, medicines, doses, and pharmacies?
- What will I pay monthly and when receiving care or filling each prescription?
- If I leave Medicare Advantage, can I buy Medigap without health questions in my state?
- Which services and medicines require approval, referrals, or trying a lower-cost option first?
- Can I use this coverage for routine care when traveling or living outside my area?
- Do I qualify for Extra Help or another program that lowers drug costs?
See the plans in your ZIP code:
How sure is this guide?
Where the four AIs disagreed
ChatGPT, Claude, Gemini and Grok each researched Medicare open enrollment on their own, with web search. The score is how closely their answers matched. Where they split, ask a licensed insurance agent or a SHIP counselor before you trust either side.
76/ 100Partial agreement
Medicare Advantage Open Enrollment Period
- GPT-5.6 Terra: Jan 1 to Mar 31; switch plans or return to Original Medicare and add Part D.
- Claude Sonnet 5.5: Jan 1 to Mar 31; says only that members can switch plans.
- Gemini 3.8 Flash: Jan 1 to Mar 31; says members can switch or drop the plan.
- Grok 4.5: Does not explain this separate period.
Sources
The AIs searched the web and used these. AI can get details wrong, so the dated numbers above are copied by hand from the official source beside each, and the plan documents you get from your insurer or employer are the final word.