Medicare Annual Enrollment 2027: What Is Changing and What to Check

The Annual Enrollment Period is for people already on Medicare. From October 15 to December 7, you can switch Medicare Advantage plans, move between Medicare Advantage and Original Medicare, or change your stand-alone Part D drug plan. Changes start January 1, 2027. A second window, the Medicare Advantage Open Enrollment Period, runs January 1 to March 31. It lets someone already in a Medicare Advantage plan switch to a different Medicare Advantage plan or go back to Original Medicare. It does not let anyone move from Original Medicare into Medicare Advantage. So the fall window is the main one, and the winter window is a limited repair option.

Every Medicare plan must send an Annual Notice of Change and an Evidence of Coverage by September 30. The notice lists the 2027 changes to your premium, deductible, copays, drug formulary, and network. Most people file it unread, and that is where surprises start. A drug that was a low-cost tier last year can move to a higher tier or need prior authorization. A hospital or specialist group can leave the network. Your plan is not required to keep looking like the one you chose. Auto-renewal means you accept whatever the notice says, so reading it is the lowest-effort way to protect yourself.

On the drug side, CMS set several 2027 Part D figures. The out-of-pocket threshold is $2,400, up from $2,100 in 2026. After you reach it, you pay nothing for covered Part D drugs for the rest of the year. The maximum standard deductible any plan can charge is $700, up from $615. The base beneficiary premium is $41.33, up from $38.99, and the national average monthly bid amount is $296.05. The Part D Premium Stabilization Demonstration, a temporary subsidy for stand-alone drug plans, ends after the 2026 plan year. Many plans charge less than the maximum deductible, so your own plan's number matters more than the cap.

CMS released projections on September 28, 2026. The average stand-alone Part D premium is projected at about $36 a month, against $35.09 in 2026, a change of under $1. The weighted average Medicare Advantage premium is projected at $12.00, against $14.37, about 16.5% lower. For Medicare Advantage plans that include drug coverage, the average Part D portion is about $7, against $11.32. About 34 million people, or 47.4% of those eligible, are projected to be in Medicare Advantage in 2027, and the plan count is roughly flat at about 5,532. Treat these as averages only. KFF and AARP, analyzing the same data, caution that stand-alone drug plans may be harder to find and more expensive for many people, and that results depend on plan and county.

Part B is the open question. The 2026 standard premium is $202.90 a month. As of early October 2026, CMS has not announced the 2027 premium, and it usually does so in the fall, often in November. The 2026 Medicare Trustees Report projects roughly $209.50 for 2027, which is an unofficial projection and could differ from the final number. IRMAA thresholds for 2027 are also not yet announced. What is already settled is the income that counts: the 2027 premium uses your 2025 MAGI, which is locked in, and the 2028 premium will use your 2026 MAGI. IRMAA also applies to Part D, and you pay that surcharge to Medicare even if your drug plan sits inside a Medicare Advantage plan.

The Medigap trap is the change people regret most. Original Medicare plus a Medigap policy works nationwide with any provider that accepts Medicare. Medicare Advantage plans use networks. If you drop Medigap for a Medicare Advantage plan and later want to return, you can face medical underwriting outside special guaranteed-issue windows, meaning an insurer may decline you or charge more based on your health. The fall window does not give you a guaranteed right to buy a Medigap policy. A low Advantage premium can look like a bargain, but it is a one-way door for many people. If you spend part of the year in Arizona and part elsewhere, check out-of-area, urgent care, and emergency coverage, and whether the plan has a travel benefit.

Start with the Annual Notice of Change and put your own numbers beside it. Use the Medicare Plan Finder at medicare.gov to enter your current drugs, dosages, and pharmacies, and compare your current plan's 2027 version with the alternatives in your county. Your state SHIP counselors, the State Health Insurance Assistance Program, can walk through the same comparison with you. Choosing a plan is a medical and coverage decision. A licensed Medicare broker or SHIP counselor can compare plans for you. Singh PWM is a flat-fee planning firm, not an insurance agency, and its role is the income, IRMAA, and cash-flow side.

The six checks are short. First, drug list and pharmacy: confirm each of your drugs is on the 2027 formulary, note its tier, and confirm your pharmacy is still in network. Second, doctors and hospitals: confirm your primary care physician, specialists, and preferred hospital are in network. Third, total yearly cost: add the premium, the deductible, the copays you expect to pay, and the out-of-pocket maximum, rather than comparing premiums alone. Fourth, prior authorization and referral rules: ask which of your services need approval first. Fifth, travel and out-of-area coverage. Sixth, whether the plan changed its Part D deductible, since the cap is rising to $700.

Many people have nothing to do. If the notice shows no changes that affect you, your drugs and doctors remain covered, and the total yearly cost is acceptable, staying put is a legitimate decision. The point is that it should be a decision, not a default. Write down your reasons and the date so you can revisit it next October. If you take few drugs and see doctors rarely, a premium change may matter more. If you take several brand-name drugs, the formulary and tier changes matter most, and the new $2,400 threshold sets the ceiling on your out-of-pocket costs for covered drugs in the year, not counting premiums or drugs your plan does not cover.

The income tie-in is where planning comes in. Your 2026 MAGI sets your 2028 Part B and Part D premiums. If you are doing Roth conversions or large IRA withdrawals this year, the IRMAA tier they land in will not show up on a bill for two years, and tiers are cliffs: $1 over a threshold triggers the full tier. For 2026, the first tier starts above $218,000 joint or $109,000 single. CMS will publish the 2027 thresholds, and the site will be updated when it does. Counting a conversion's two-year IRMAA cost alongside its income tax cost is the part most people skip.

If you are thinking of leaving a Medigap policy, treat that as a separate, slower decision. Check what happens if you want to return, and do not assume you can. If you are new to Medicare or still working at 65, different rules and deadlines apply, covered in the related guides below. A late Part D enrollment carries a lifetime penalty of 1% of the national base beneficiary premium ($41.33 in 2027) for each full month you went without creditable coverage, so do not let a drug plan lapse by accident.

• Filing the Annual Notice of Change unread and letting the plan auto-renew, then discovering in January that a drug moved to a higher tier or a doctor left the network.
• Comparing premiums alone and ignoring the deductible, copays, and out-of-pocket maximum, which together make up the real yearly cost.
• Relying on national averages from CMS projections to predict what your own plan in your own county will do, since individual results vary widely.
• Dropping a Medigap policy for a low-premium Medicare Advantage plan without checking whether medical underwriting could block a return to Original Medicare later.
• Waiting until December 7 to start, then finding that a pharmacy check or plan call takes longer than expected.
• Ignoring the two-year IRMAA lookback when making Roth conversions or large IRA withdrawals this year, which sets 2028 premiums.
• Letting a stand-alone Part D plan lapse, which can trigger a lifetime late enrollment penalty.