Medicare open enrollment 2027: lower average premiums, and the fine print that decides your bill

Medicare’s annual Open Enrollment runs from October 15 to December 7, 2026. Anything you change in that window takes effect January 1, 2027, and the window is the only time most beneficiaries can move between Original Medicare and Medicare Advantage, switch Advantage plans, or join, drop or change a stand-alone prescription drug plan.

This year the headlines are unusually friendly — and unusually easy to misread. Here is what CMS actually published on September 28, 2026, and where the averages stop being useful.

The headline: Advantage premiums down, on average

CMS projects the weighted average monthly Medicare Advantage premium to fall from $14.37 in 2026 to $12.00 in 2027 — a decline of 16.5%.

Measure (national average)	2026	2027	Change
Medicare Advantage monthly premium (weighted)	$14.37	$12.00	−$2.37 (−16.5%)
Drug-coverage portion inside an MA drug plan (after rebates)	$11.32	$7.00	−$4.32 (−38%)
Stand-alone Part D drug plan (total average premium)	$35.09	$36.00	+$0.91 (under $1)
Number of Medicare Advantage plans nationally	5,553	about 5,532	−21

The rest of CMS’s release is stability, not drama: more than 99% of beneficiaries will have at least one Advantage plan available and 97% will have ten or more choices; about eight in ten current Advantage members can keep their plan at the same or a lower premium; supplemental benefits such as dental, vision and hearing are expected to hold steady; and enrollment is projected at about 34 million people, or 47.4% of everyone with Medicare.

Every one of those numbers is a national weighted average. None of them is your bill. Averages are calculated across every plan in every county, and an individual plan can raise its premium in a year when the average falls. Read the table as context, not as a forecast.

Where the averages mislead the most

Look at the two drug rows together. Drug coverage inside a Medicare Advantage plan falls sharply (to $7 on average), while a stand-alone Part D plan used alongside Original Medicare drifts slightly up, from $35.09 to $36. The gap between those two numbers is the whole story of the stand-alone drug market: Advantage plans can use rebates to buy down drug premiums, and stand-alone plans cannot.

There is a second reason to expect the stand-alone average to understate what some people pay. CMS is ending the temporary Part D Premium Stabilization Demonstration after 2026 — a program established in 2024 that reduced the base beneficiary premium and capped year-over-year increases for stand-alone plans. KFF’s analysis, published in July 2026, notes that the demonstration cost $9.8 billion across 2025 and 2026 and that, without it, some stand-alone drug plan enrollees could face a larger premium increase for 2027 than in recent years. CMS’s own position is that the market is stable and that plan sponsors no longer need the support.

The practical reading: if you are in Original Medicare with a stand-alone drug plan, this is a year to actually compare rather than renew on autopilot. If you are in a Medicare Advantage plan, compare your plan’s own 2027 numbers instead of the national average.

Four checks before you switch anything

1. Your doctors. Plan directories go stale. Call the office and ask whether it will accept that specific plan in 2027 — a network change costs more than a premium change.
2. Your prescriptions. Enter every drug into the Medicare Plan Finder on Medicare.gov and check the tier, the pharmacy network and any prior-authorization rules. A $0 premium plan can cost more over a year if one of your medications sits on a high tier.
3. The out-of-pocket maximum. The annual cap is the number that matters if you expect surgery, ongoing treatment or frequent specialist visits. It can move even when the premium does not.
4. Whether your plan still exists. If an insurer is leaving your market, the plan is not an option to keep. Your plan must send you an Annual Notice of Change each fall; if you have not received one, call the plan’s member-services line and ask what happens on January 1.

If you want help going through it, 1-800-MEDICARE (1-800-633-4227) is staffed 24 hours a day, and Medicare.gov lists the free counseling available through your State Health Insurance Assistance Program. CMS also publishes 2027 landscape files and state-by-state fact sheets if you want the raw plan data.

Two things this window is not

It is not the deadline for signing up for Medicare in the first place. If you are approaching 65, your Initial Enrollment Period is a seven-month window around your birthday and has nothing to do with October 15. Getting these two calendars confused is how people end up paying a permanent late-enrollment penalty; the details are in our guide Medicare Enrollment Is Moving Toward America.gov.

It is not an America.gov service — yet. CMS’s plan-year release sends beneficiaries to Medicare.gov, the Plan Finder and 1-800-MEDICARE, and does not mention the new federal portal. Decisions for 2027 run on the CMS calendar, not the portal’s roadmap.

The scam season that comes with it

Open enrollment is peak season for Medicare fraud, because millions of people are expecting to be contacted about their coverage. The tells are consistent:

• Nobody legitimate calls to sell you a plan or to “review your Medicare.” Agents must follow marketing rules, and 1-800-MEDICARE is not going to cold-call you about a better plan.
• Never give your Medicare number to someone who contacted you first. That number is the keys to your coverage and your medical identity.
• “Your plan is being cancelled, act now” is the pressure line. Real plan changes come by mail, in writing, with a date.
• Medicare, Social Security and CMS do not charge a fee to enroll, switch plans or “hold your coverage.”

If something sounds off, hang up and call 1-800-MEDICARE yourself, or report it to the FTC at reportfraud.ftc.gov. Our companion guide Is That Really America.gov? A Scam-Spotting Checklist applies here too.

Bottom line

The average Advantage premium is genuinely falling for 2027, but the average is not your bill — and if you are on a stand-alone drug plan, the direction of the average is not reassuring. Take the four checks in order, use the Plan Finder with your actual prescriptions, and finish before December 7, 2026. People who read their plan’s notice and shop once a year reliably do better than people who assume this year looks like last year.