Open Enrollment for 2027 coverage runs October 15 through December 7, and any change you make by that deadline takes effect January 1. Before you touch an enrollment form, read your Annual Notice of Change, check your plan's formulary and provider network for 2027, and pull together your current medication and pharmacy lists. From there, Medicare Plan Finder and resources like 1-800-MEDICARE, your local SHIP, or a licensed advisor can help you compare options with confidence.
TL;DR:
- Your plan sends its Annual Notice of Change and Evidence of Coverage in late September; review both before comparing 2027 premiums, benefits, drugs, and networks.
- Medicare Advantage members can make one additional plan switch from January 1 through March 31, while Special Enrollment Periods cover qualifying events such as moving.
- The 2027 national average monthly bid amount is $296.05, but it does not predict your plan’s premium or coverage; compare your own notice.
- Enter medication names and dosages, preferred pharmacy, and regular providers in Medicare Plan Finder; check drug tiers and network status, then total annual costs.
Table of Contents
- Prepare a Timeline and Key Dates for Open Enrollment 2027
- Exactly What You Can Change During Open Enrollment
- 2027 Policy Updates and Numbers That Matter When Choosing a Plan
- How to Compare Plans for 2027 Using ANOC, Plan Finder, and Formularies
- A Short, Ordered Checklist to Complete Before December 7
- Advisor Perspective: Common Pitfalls and How Licensed Advisors Help
- What Open Enrollment Research Actually Tells Us
- How Platinum Benefit Advisors Can Help You Enroll or Switch Plans
- FAQ
- Sources
Prepare a Timeline and Key Dates for Open Enrollment 2027
Open Enrollment moves fast once it starts, so the groundwork matters more than the six-week window itself.
- Late September: your plan sends an Annual Notice of Change (ANOC) and Evidence of Coverage (EOC) describing what's different for 2027.
- October 1: start comparing plans and gathering documents, including your medication list and provider contacts, according to Medicare's own guidance.
- October 15 to December 7: the Open Enrollment window during which you can switch, join, or drop coverage for 2027.
- January 1: any change submitted and processed by December 7 takes effect.
- January 1 to March 31: the Medicare Advantage Open Enrollment Period (MA OEP) allows a narrower set of changes if you're already in an MA plan.
Missing the October 15 start is common and costly: reviewing your ANOC the moment it arrives gives you the most runway to compare alternatives.
Exactly What You Can Change During Open Enrollment
Open Enrollment gives you real flexibility, but it's worth knowing precisely what's on the table. During this window, you can switch between Original Medicare and Medicare Advantage, move from one Medicare Advantage plan to another, or join, drop, or change a standalone Part D plan.
- Switch from Original Medicare to a Medicare Advantage plan, or move back to Original Medicare.
- Change from one Medicare Advantage plan to a different one, including plans that bundle drug coverage (MA-PD).
- Join a Part D plan for the first time, switch to a different one, or drop drug coverage entirely.
What you generally cannot do during this window is make mid-year changes outside these categories. If you're already enrolled in Medicare Advantage, the separate MA OEP from January through March allows one additional plan switch, and Special Enrollment Periods cover situations like moving or losing employer coverage. Our overview of Special Enrollment Period rules walks through those exceptions in more detail.
2027 Policy Updates and Numbers That Matter When Choosing a Plan
CMS has stated that the Medicare Advantage and Part D markets are expected to remain stable for 2027, which is reassuring at a headline level but doesn't replace reading your own plan's materials.
The national average monthly bid amount (NAMBA) for 2027 is $296.05, the enrollment-weighted average of Part D basic bids that factors into how premiums and federal subsidies are calculated across plans.
That bid data feeds directly into what you'll see on your ANOC: premium adjustments, formulary tier shifts, and changes to subsidy calculations all trace back to these technical figures. The Part D Premium Stabilization Demonstration, which had been smoothing certain premium increases in recent years, is winding down, and plans may price differently as a result. None of this tells you what your specific plan will charge or cover next year. It tells you why the number on your notice might look different from last year's, and why comparing rather than assuming is the safer move.
How to Compare Plans for 2027 Using ANOC, Plan Finder, and Formularies
A methodical comparison takes less time than you'd think if you work through it in order.
- Read your ANOC and EOC first. These documents spell out changes to premiums, benefits, drug formularies, and provider networks for 2027, and they're the fastest way to spot a problem before it becomes expensive.
- Build your profile in Medicare Plan Finder. Enter your current medications with dosages, your preferred pharmacy, and the providers you see regularly so the tool can compare plans against your actual needs rather than generic averages.
- Check pharmacy status and drug tiers. A plan's preferred pharmacy network and how it tiers your specific medications can swing your costs more than the premium does.
- Add up the annual total, not just the monthly premium. Combine premium, expected copays or coinsurance, and pharmacy costs to see what the plan actually costs you over the year.
Medicare Plan Finder pulls plan documents and provider information together in one place, which makes side-by-side comparison far easier than reading PDFs one at a time.
Pro Tip: Run your medication list through Plan Finder even if you're happy with your current plan: formularies shift every year, and a drug that was covered at a low tier in 2026 can move to a higher tier for 2027.
A Short, Ordered Checklist to Complete Before December 7
Turning the research above into action is mostly a matter of sequencing.
- Gather your ANOC/EOC, current medication list, preferred pharmacy details, and insurance cards.
- Run comparisons in Medicare Plan Finder and save the EOC and formulary for each plan you're seriously considering.
- Confirm your key providers are in-network and check pharmacy pricing for your most important medications.
- Submit your enrollment choice before December 7, then confirm the plan received it.
- Track your confirmation and watch for a welcome packet or ID card before January 1.
- If anything is unclear, call 1-800-MEDICARE, contact your local State Health Insurance Assistance Program, or reach out to a licensed advisor for help.
Our Michigan-specific Medicare guide for 2027 walks through how these steps apply to Advantage, Part D, and Medigap choices for the coming year.
Advisor Perspective: Common Pitfalls and How Licensed Advisors Help
The pitfalls we see most often during Open Enrollment are predictable: skipping the ANOC entirely, assuming a formulary hasn't changed, or overlooking that a pharmacy moved from preferred to standard status. Any one of these can turn a plan that looked affordable in October into a costly surprise by March.
A licensed advisor's work is mostly about catching these details before they become problems. That means prefilling a client's medication list into Plan Finder, checking provider directories line by line against a client's actual doctors, confirming pharmacy tier placement, and estimating a realistic annual cost rather than just comparing premiums. It's detail work, and it's exactly the kind of review that gets skipped when people are rushed or unfamiliar with where plans tend to change year to year.
What Open Enrollment Research Actually Tells Us
The most overrated piece of advice we hear every fall is "if your plan isn't changing much, you don't need to do anything." Technically true, practically risky: a stable-looking premium can hide a formulary tier change or a pharmacy network shift that costs you hundreds of dollars before you notice.
What the evidence actually supports is narrower and more useful: read the ANOC first, because that single document flags almost every change that matters. CMS's own stability outlook for 2027 is a market-level signal, not a guarantee about your plan, and treating it as reassurance to skip your own review is the mistake that costs people money. If you prioritize one thing this fall, make it the formulary and pharmacy check, since that's where real dollars hide while premiums stay flat.
— Brian
How Platinum Benefit Advisors Can Help You Enroll or Switch Plans
We offer advisory help to compare Medicare plans and complete enrollment. Rather than working through Plan Finder, formularies, and provider directories alone, you can sit down with an advisor who checks those details against your actual medications and doctors, then handles the paperwork with you.
Have questions? We have answers! Contact us to schedule a no-obligation meeting. Call or text 616-221-4616. Meet on your terms: in person, by phone, or virtually.
Scheduling before December 7 gives us time to verify your plan's formulary, confirm your providers are in network, and submit your enrollment so it's processed well ahead of the deadline. You can also start by visiting our Medicare services page to see how we support people approaching eligibility or reviewing existing coverage.
This article is general information, not a substitute for advice from a qualified doctor. Consult a qualified healthcare professional about your own circumstances before acting on anything here.
FAQ
What is the biggest mistake seniors make when enrolling in Medicare?
The most common mistake is skipping the Annual Notice of Change and assuming last year's plan still covers the same drugs and doctors. Formularies and provider networks shift every year, so a quick ANOC review before Open Enrollment starts catches most problems early.
How much will Medicare cost in 2027?
Costs vary by plan, but CMS has tied 2027 Part D pricing to a national average monthly bid amount of $296.05, which factors into premium and subsidy calculations. Your actual premium and out-of-pocket costs depend on the specific plan you choose, so comparing options in Medicare Plan Finder is the only way to get a figure that applies to you.
Can I choose my start date for Medicare?
For Open Enrollment changes, the start date isn't flexible: any switch processed by December 7 takes effect January 1 of the following year. Enrollment tied to qualifying events follows different timing rules.
Can I drop my Medicare Advantage plan and go back to Original Medicare?
Yes, switching from Medicare Advantage back to Original Medicare is one of the changes allowed during Open Enrollment. You can also make this switch during the separate Medicare Advantage Open Enrollment Period from January 1 through March 31 if you're already enrolled in an MA plan.
Sources
- Medicare Advantage and Medicare Prescription Drug Programs Expected to Remain Stable in 2027 | CMS
- Open Enrollment | Medicare