There is exactly one stretch of the year when you get to push back on what Medicare costs you, and it starts October 15. From then until December 7, Medicare's Annual Enrollment Period lets anyone on Medicare switch Part D drug plans, jump between Original Medicare and Medicare Advantage, or change Advantage plans for 2027 coverage that begins January 1. Miss it, and for most people the choices lock until next fall. Yet a Kaiser Family Foundation analysis found that nearly 7 in 10 beneficiaries — about 69% — never compared their coverage against other options during open enrollment, with traditional Medicare enrollees the least likely to shop at all. That inertia has a price every year. It has a bigger one in 2027, when the drug deductible, the out-of-pocket cap, and the Part B premium are all moving up at once. Here is how to treat these seven weeks like the money decision they are.
The Deadline That Doesn't Wait
The Annual Enrollment Period runs October 15 through December 7, 2026. Anything you change in that window takes effect January 1, 2027. After December 7, your options narrow sharply: the Medicare Advantage Open Enrollment Period (January 1 to March 31) lets Advantage members make one switch, but people on Original Medicare and standalone Part D plans generally cannot change again until the next fall.
The reason this matters is simple: plans are not static. Insurers reset premiums, deductibles, drug formularies, pharmacy networks, and prior-authorization rules every single year. The plan that was the cheapest fit for your prescriptions in 2024 can quietly become one of the most expensive by 2027 — and nobody mails you a warning. If you do nothing, you are auto-renewed into next year's version of your current plan, whatever it has become.
What's Actually Changing in 2027
Several of the headline numbers below come from the 2026 Medicare Trustees Report and are projections until the Centers for Medicare & Medicaid Services finalizes them, typically in late October or early November. The Part D structural figures, however, are already set in the law's inflation-adjusted formula.
- Standard Part D deductible: rising to $700, up from $615 in 2026 — an increase of roughly 14%, the largest single piece of bad news in the 2027 numbers.
- Part D out-of-pocket cap: climbing to $2,400, up from $2,100. The catastrophic ceiling that protects you kicks in once your total drug spending (what you and the plan pay combined) reaches about $7,500. Premiums don't count toward it.
- Part B premium: projected at about $209.50 a month, up from $202.90 — roughly a 3.25% bump, far milder than the prior year's near-10% jump, though CMS could still finalize it higher.
- Part B deductible: projected to rise to about $292, from $283.
- Part A hospital deductible: projected at roughly $1,788 per benefit period, up from $1,736.
- Average standalone Part D premium: projected to tick up less than a dollar, from $35.09 to about $36 — the averages are calm, but individual plans can still swing by a lot.
The Costly Habit Hiding in Auto-Renewal
Why does not shopping cost real money? Because Part D in particular is built to reward people who re-check every year. A plan can drop one of your medications from its formulary, move it to a higher cost tier, raise its deductible to the new $700 ceiling, or narrow its preferred-pharmacy network — and your total annual cost can jump by hundreds of dollars without the sticker premium changing much at all.
KFF's research found that the beneficiaries least likely to compare plans were also, in past surveys, among the most likely to call the process frustrating and difficult. That is understandable. But the fix is not to tough out a confusing system — it is to run one structured review a year, during the only window that lets you act on what you find.
Your 5-Step Plan-Review Playbook
- Step 1 — Pull your drug list first. Write down every prescription you take, the exact dose, and your preferred pharmacy. This single list drives the entire comparison; guessing is how people end up overpaying.
- Step 2 — Read your Annual Notice of Change. Your plan mailed (or emailed) an ANOC in September spelling out exactly what changes January 1. Find the premium, deductible, drug-tier, and network changes. If your drugs moved tiers or dropped off, treat that as a flashing light to shop.
- Step 3 — Run your drugs through the official Medicare Plan Finder at Medicare.gov. Enter your medications and pharmacy, and it ranks every plan available in your ZIP code by estimated total annual cost — premiums plus deductible plus copays — not just the monthly premium. The lowest-premium plan is frequently not the cheapest once your prescriptions are factored in.
- Step 4 — Compare Original Medicare vs. Medicare Advantage honestly. Advantage plans often advertise $0 premiums but carry networks, referrals, and prior authorizations; Original Medicare plus a standalone Part D plan (and possibly a Medigap policy) offers broader provider access at a higher fixed cost. The right answer depends on your doctors, your drugs, and how much travel or snowbirding you do.
- Step 5 — Lock it in before December 7. Once you've found the plan that covers your drugs and doctors for the lowest total cost, enroll. Coverage starts January 1, and you'll have confirmation that you reviewed — rather than drifted into — your 2027 plan.
Two Wild Cards to Watch
First, there's relief on the table: AARP reports a one-time $90 rebate announced for roughly 20.8 million Original Medicare beneficiaries to help offset Part B costs — worth confirming your eligibility once details are finalized. Second, don't confuse the base Part D premium ($41.33, a benchmark used for penalties and high-income surcharges) with what you'll actually pay; your real premium depends on the specific plan you choose, which is exactly why the Plan Finder comparison in Step 3 matters more than any single headline number.
The Raise You Won't Actually Feel
Here's the part that ties Medicare back to your whole retirement income. The Social Security Administration announces the 2027 cost-of-living adjustment on October 14, with early estimates clustering around 3.5%. But your Part B premium is deducted from your Social Security check before it hits your bank account — so your true raise is the COLA minus whatever Medicare takes back. With Part B projected up about 3.25%, a chunk of the headline increase evaporates on arrival, and higher earners subject to IRMAA surcharges can see even more of it absorbed.
That interplay is why the Medicare decision and the Social Security decision aren't separate. If you're approaching 65 and weighing when to claim benefits while enrolling in Medicare for the first time, the timing of your claim changes the base that every future COLA — and every Medicare deduction — is calculated against. LoanPal's Social Security Optimizer lets you model different claiming ages so you can see how the net check, after Medicare, actually shakes out over a full retirement.
Medicare is one of the largest fixed expenses in retirement, and open enrollment is the rare moment when it's negotiable — not with an insurer, but with your own willingness to spend an hour comparing. The 2027 numbers aren't catastrophic, but the 14% jump in the drug deductible and the steady creep in Part B premiums reward the people who look and penalize the people who drift. Put October 15 to December 7 on the calendar, pull your drug list, run the Plan Finder, and decide on purpose. Then use the Social Security Optimizer to see what your 2027 check really looks like once Medicare takes its cut — because the only number that matters is the one that actually reaches your account.
