Medicare Open Enrollment 2027: What’s Changing and the Dec. 7 Deadline

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Medicare Open Enrollment for 2027 coverage is already underway: it runs from Thursday, October 15 through Monday, December 7, 2026, and any change you make takes effect on January 1, 2027. Medicare.gov sets one hard rule on timing: your plan must receive your enrollment request by December 7.

This year the national averages look calmer than many people expected. The Centers for Medicare & Medicaid Services (CMS) projects the average Medicare Advantage premium will fall 16.5% in 2027, and standalone Part D drug-plan premiums will rise by less than $1 a month. Those are projections for the whole market, not a promise about your plan — which is exactly why CMS frames this window as a review exercise, not a shopping holiday. Your premium, your drug list, your doctors’ network, and your cost-sharing can all move on January 1 even if you change nothing.

The dates that decide your 2027 coverage

What you can change before December 7

Medicare.gov lists the moves available during Open Enrollment, depending on the coverage you have now:

• Medicare Advantage members can join, drop, or switch to another Medicare Advantage plan — with or without drug coverage — and can add or drop drug coverage.
• Original Medicare members can join, drop, or switch to another standalone Part D drug plan.
• Anyone can switch how they get coverage: from Original Medicare to a Medicare Advantage plan, or from a Medicare Advantage plan back to Original Medicare.

The last move carries a warning worth reading twice. If you leave Medicare Advantage for Original Medicare, you may want to add a Part D plan and a Medicare Supplement Insurance (Medigap) policy to cover Original Medicare’s cost-sharing. Medicare.gov is explicit: there are limits on when you can add Medigap, so check whether you can get that coverage before you switch — leaving Advantage for Original is easy, getting a Medigap policy later is not guaranteed.

What CMS says 2027 looks like — the official projections

On September 28, 2026, CMS released its 2027 preview. Every figure in this table is a projection, not a rate you will pay:

CMS also projects the market stays broad: more than 99% of beneficiaries will have access to at least one Medicare Advantage plan, 97% will have 10 or more choices, the national plan count holds roughly steady (5,553 in 2026 to about 5,532 in 2027), and about eight in 10 MA members will be able to stay in their current plan at the same or a lower premium. Projected MA enrollment is about 34 million — roughly 47.4% of everyone in Medicare.

On the Part D side, the end of the temporary Premium Stabilization Demonstration after 2026 did not break the market, per CMS: 88% of non-low-income beneficiaries will have access to a basic Part D plan costing $10.30/month or less, and 93% will have access to an enhanced Part D plan under $6/month.

One number that is not in this preview: the 2027 standard Part B premium and deductible. CMS announces Parts A & B premiums and deductibles separately from the MA/Part D preview — the 2026 standard Part B premium was $202.90/month (confirmed on Medicare.gov). If you read a 2027 Part B figure before CMS announces it, treat it as preliminary. If you also receive Social Security, note that the 2027 COLA raises benefits by 3.6% starting in January — see our Social Security COLA 2027 guide for the new amounts and payment dates.

The 2027 Part D standard benefit: $700 deductible, $2,400 cap

Separate from premiums, CMS finalized the 2027 defined standard Part D benefit in its April 2026 rate announcement:

The cap is the protection that matters most if you take expensive drugs: once your out-of-pocket spending on covered Part D drugs reaches $2,400 in 2027, you pay nothing more for covered drugs for the rest of the calendar year. Premiums do not count toward it, and neither do drugs your plan does not cover.

A detail people miss: because the cap is measured at 25% coinsurance after the deductible, the total drug spending needed to reach the cap rises with it. Under the 2027 standard benefit you would need about $7,500 in covered drug costs to hit the $2,400 cap ($700 deductible + $1,700 in coinsurance ÷ 25%). In 2026 the equivalent figure was about $6,555. The safety net is real, but it now sits slightly farther away.

Three drug years, worked out under the 2027 standard benefit

These illustrative examples use the defined standard benefit exactly — $700 deductible, 25% coinsurance, $2,400 out-of-pocket cap — and assume no Extra Help. Real plans often use copay tiers instead of the textbook structure, and a plan’s own deductible may be lower than $700, so treat these as the outline of the protection, then check your plan’s numbers.

Notice who the cap helps and who it doesn’t: the generics-only year costs the same with or without the cap, while the specialty year turns a $60,000 bill into a known $2,400 maximum. That is the entire logic of comparing plans by total yearly cost — premium plus your expected drug cost-sharing — rather than by premium alone.

What this means for you

• If your drugs cost little: the $2,400 cap will likely never matter to you. Your comparison is mostly premium vs. deductible, and whether your generics are on a low tier or $0 tier.
• If you take a brand-name or specialty drug: the formulary and the tier your drug sits on matter more than the premium. One plan’s $36/month premium with your drug uncovered is worse than a $60/month premium with it covered. Run your exact prescriptions through Medicare Plan Finder.
• If you are in Medicare Advantage: you get a second, narrower window — the Medicare Advantage Open Enrollment Period, January 1 to March 31 — to switch to a different MA plan or drop MA for Original Medicare with a standalone Part D plan. Changes take effect the first of the month after the plan receives your request. December 7 is still your main deadline.
• If you are in Original Medicare with Medigap: Open Enrollment does not give you a guaranteed right to switch Medigap plans — medical underwriting can apply outside your initial window — so price your Medigap alongside your Part D comparison.
• If money is tight: Medicare Savings Programs can help pay premiums, deductibles, and copayments, and Extra Help pays Part D premiums, deductibles, and coinsurance for qualifying individuals. CMS notes that enrolling in a Medicare Savings Program also qualifies you for Extra Help automatically. Both are worth checking before you pick a plan on price alone.

The penalties for sitting out

Open Enrollment is also the moment to make sure you are not about to earn a penalty that follows you for life. Medicare.gov’s rules:

• Part B: an extra 10% on your premium for each full 12-month period you could have had Part B but didn’t — added for as long as you have Part B. Two years late means 20%: on the 2026 standard premium of $202.90, that is $40.58 extra, or $243.50/month (rounded to the nearest $0.10).
• Part D: an extra 1% for each month (12% a year) you went without creditable drug coverage after becoming eligible — added to your plan’s premium for as long as you have drug coverage, even if you switch plans. It is calculated from the national base beneficiary premium ($38.99 in 2026).

Both penalties are waived in the usual safe cases: employer coverage that counts as creditable, qualifying for Extra Help (Part D), or a Special Enrollment Period.

Your open-enrollment checklist

1. Open your plan’s notice of 2027 changes. Plans began notifying enrollees in September; the notice describes your plan’s 2027 premium, formulary, and network — not the national averages above. The “2027 Medicare & You” handbook was also mailed to every Medicare household in September.
2. List your prescriptions and your doctors. Exact drug names and doses; the doctors and pharmacy you actually use.
3. Run the comparison at medicare.gov. Medicare Plan Finder compares the same drugs and pharmacy across every 2027 plan in your area, showing estimated total yearly cost — not just premiums.
4. Check the plan’s 2027 Star Rating. CMS published the 2027 ratings on October 8, 2026, and they appear in Plan Finder. About 37% of Medicare Advantage drug-plan contracts (188) earned 4 stars or more — covering roughly 71% of enrollees — and 15 contracts earned 5 stars; the enrollment-weighted average slipped to 3.99 from 4.01. Standalone Part D plans improved: about 22% of their enrollees are now in 4+ star contracts, up from 2% last year. Use the rating as a quality check, not the deciding vote.
5. Call your doctors about the network. Directories can lag; a two-minute call confirms your doctor is in the 2027 network.
6. Check Extra Help and Medicare Savings Programs. Apply at ssa.gov/extrahelp or through your state if your income and resources are limited.
7. Act by December 7. The plan must receive your enrollment request by December 7, 2026. If you do nothing and your plan is still offered, you are generally renewed automatically — with the 2027 changes included, like it or not.

Where to get free help

You do not have to do this comparison alone, and the free options have no financial interest in which plan you pick:

• 1-800-MEDICARE (1-800-633-4227) — help comparing plans and costs, 24 hours a day, 7 days a week.
• Medicare Plan Finder at medicare.gov — the official comparison tool with 2027 plan, premium, cost, and benefit data.
• Your State Health Insurance Assistance Program (SHIP) — free, local, one-on-one counseling from counselors with no ties to any insurance company.

Frequently asked questions

If the averages look good, can I just keep my plan and skip the review?

Probably — if you like your plan, CMS says people who want to keep their current coverage generally do not need to re-enroll. But “no action” still means you accept the 2027 version of the plan: the premium, drug list, pharmacy network, and prior-authorization rules can all change on January 1. Reading the Annual Notice of Change is the minimum; running your drugs through Plan Finder takes it from a guess to a number.

Is the $12 average Medicare Advantage premium what I will pay?

No. $12 is CMS’s projected weighted average across every Medicare Advantage plan in the country, including Special Needs Plans, for 2027. Your plan’s premium is set by its own bid and your county — it can be $0, $12, or several times that. The same goes for the $36 standalone Part D average. Use the averages as a read on the market, and your ANOC and Plan Finder for your actual price.

What happens if I miss the December 7 deadline?

In most cases your current plan renews as-is for 2027 and you are locked in until next fall’s open enrollment. One exception: people already in a Medicare Advantage plan get the Medicare Advantage Open Enrollment Period, January 1 to March 31, 2027, to switch to a different MA plan or return to Original Medicare with a standalone drug plan (Indiana SHIP, an official state counseling program).