Medicare Advantage members heading into this fall’s Open Enrollment have a headline number worth reading carefully. The Centers for Medicare & Medicaid Services says roughly eight in ten Advantage members can stay in their current plan in 2027 at the same or a lower premium. The arithmetic runs the other way for the remainder: about two in ten, on that same measure, face a plan that costs more or looks different, and Open Enrollment, which runs October 15 to December 7, is the window to act.
What the kit holds: The 2027 Medicare Open Enrollment Decision Kit pairs a cost calculator spreadsheet that weighs plans on cost, drugs and doctors with a dated Open Enrollment calendar.
Open the cost calculator and calendar before the October 15 start →
The eight-in-ten figure, and the two in ten left over
The wording matters here, because it is easy to stretch. In its September 28 landscape release, CMS says approximately eight in 10 Medicare Advantage beneficiaries will be able to remain in their current plan with the same or a lower premium in 2027. Subtracting from ten leaves roughly two in ten members whose current plan will carry a higher premium or will not be there to stay in. CMS does not say two in ten lose their plan outright, and it does not split the remainder between a price increase and a plan that is discontinued.
Scale makes the leftover group large. CMS estimates 2027 Advantage enrollment at 34 million people, about 47.4 percent of everyone in Medicare. Two in ten of 34 million is on the order of 6.8 million members, a back-of-envelope figure derived from the agency’s two numbers rather than a count CMS publishes.
5,532 plans, down from 5,553
The same release counts approximately 5,532 Medicare Advantage plans available for 2027, a small step down from 5,553 in 2026. Access stays broad: more than 99 percent of beneficiaries can reach at least one Advantage plan, and 97 percent can choose among ten or more, according to the agency.
CMS also projects the weighted average monthly Advantage premium to fall from $14.37 this year to $12.00 in 2027, a decline of 16.5 percent. For Advantage plans that include drug coverage, the average monthly Part D premium is projected to drop from $11.32 to $7, a decrease of $4.32 a month, or 38 percent. CMS says supplemental benefits such as hearing, dental and vision are expected to remain stable. CMS Administrator Dr. Mehmet Oz credited the stability to “slashing handouts to big insurance companies,” and the release adds that 93 percent of non-low-income beneficiaries can reach an enhanced Part D plan for less than $6 a month, while 88 percent can reach a basic plan at $10.30 or less.
Why a lower average does not settle one member’s year
An average across thousands of plans can fall while an individual plan rises, which is why the eight-in-ten framing deserves attention. A member in the two-in-ten group could see a higher premium, a changed benefit or a different network. The ordinary route to find out is the plan’s own Annual Notice of Change, followed by a comparison against alternatives in the Medicare Plan Finder, which CMS describes as a tool for comparing health and drug plans on premiums, costs and benefits.
The 2027 contract-year rules add some context for what plans may offer. A CMS fact sheet on the 2027 final rule says supplemental-benefit cards must be tied to plan-covered items through a real-time mechanism, and that plans must publicly post their eligibility criteria for certain supplemental benefits. Both affect what a member can verify before enrolling.
The Open Enrollment calendar: October 15 to December 7
Open Enrollment for 2027 coverage opens October 15 and closes December 7, 2026, according to the CMS release. Coverage chosen in that period takes effect with the new plan year. Medicare’s own cost page still lists only 2026 premium and deductible amounts, so the comparison for next year has to lean on each plan’s own 2027 documents.
Members who like their plan and see no change in the notice may have little to do. Members whose notice shows a higher premium, a doctor dropped from the network or a drug moved to a higher tier are the group the two-in-ten arithmetic describes.
Five thousand plans, one drug list: where the comparison gets hard
The difficulty is the number of moving parts, not a lack of information. With 5,532 plans on offer nationally, a member’s county narrows the list, but each remaining plan still has its own formulary, network and yearly cost. The premium CMS averages is only one input to what a plan costs over twelve months; a lower premium paired with a drug in a higher tier, or a preferred doctor outside the network, can cost more over a year than a pricier plan that covers both.
Because the eight-in-ten figure is a national measure, it says nothing about whether a specific member’s own plan is in the two-in-ten group. That answer sits in the plan’s notice and in the 2027 plan details, and the dates run on a fixed clock that ends December 7.
The free official route is the Medicare Plan Finder at medicare.gov, which lets a member enter a drug list and compare plans, or a call to 1-800-MEDICARE; neither costs anything.
Re-shopping a plan before the December 7 close
The CMS landscape puts roughly eight in ten Medicare Advantage members in a plan they can keep at the same or a lower premium, which leaves the remainder to sort out a repriced or ended plan inside a seven-week window. That sorting runs through each plan’s drug list, network and out-of-pocket maximum, not through the premium line alone.
The 2027 Medicare Open Enrollment Decision Kit adds a provider call script and the guaranteed-issue rights section on returning to Original Medicare to its 42 pages, so doctor questions and Medigap questions can be put to the right office in order.
Get The 2027 Medicare Open Enrollment Decision Kit →
This report was drafted with AI assistance and checked line by line against the CMS release and the other linked pages.
