Medicare Open Enrollment: How to Compare Plans and Avoid Common Mistakes

Medicare Open Enrollment is here, and two plans that look nearly identical in an advertisement can leave you with dramatically different medical bills. A $0 Medicare Advantage premium does not necessarily mean $0 in health care costs. A prescription drug plan with the cheapest monthly premium may cost more over a full year if your medications are placed on expensive tiers or your pharmacy is not preferred. And switching away from a plan that works well may affect doctors, coverage approvals and future Medigap options.

For the 2027 coverage year, the Annual Medicare Open Enrollment Period runs from October 15 through December 7, 2026. Elections received by the deadline generally take effect on January 1, 2027. The official Medicare Plan Finder already provides plan options for 2027. This guide explains exactly how to compare them, how to calculate a realistic cost rather than trusting premiums alone, and which mistakes can be difficult or expensive to undo.

Scope: This is general education for people in the United States who already have Medicare or are helping a family member review Medicare. It is not individualized insurance, medical or legal advice. Availability, networks, premiums and cost sharing depend on ZIP code, plan, medications and eligibility. Always confirm final details directly with Medicare, the plan and treating clinicians before submitting an application.

Medicare Open Enrollment 2026: the essential dates for 2027 coverage

The December 7 deadline refers to the plan receiving your enrollment request, not merely your beginning the form that evening. Save confirmation numbers or screenshots. Medicare explains the dates and permitted changes on its official Open Enrollment page. The separate January–March Medicare Advantage period is described in the enrollment rules; it is not a second general opportunity for people with Original Medicare to join a drug plan without another qualifying election period.

What can you change between October 15 and December 7?

• Switch from one Medicare Advantage plan to another, including changes in drug coverage where permitted.
• Move between Original Medicare and Medicare Advantage if eligible; review Part D and Medigap consequences before deciding.
• Join, drop or switch a stand-alone Part D prescription drug plan if you have Original Medicare.
• Keep the coverage you have if its benefits, costs and network still meet your needs—but review changes first.

Open Enrollment is an opportunity to review—not a requirement to switch. The plan that fits your prescriptions, clinicians and financial risks matters more than an advertised discount or a generic “best plan” ranking.

First, identify the type of Medicare coverage you have

Before opening a comparison tool, look at your Medicare and insurance cards, recent Explanation of Benefits statements, and any plan notices. It is surprisingly easy to compare the wrong products: a stand-alone Part D drug plan is not a substitute for comprehensive Medicare Advantage health coverage, and a Medigap policy is not a Medicare Advantage plan.

Under Medicare’s official side-by-side comparison, Original Medicare generally allows any U.S. doctor or hospital accepting Medicare, while Medicare Advantage may use networks and prior authorization. Conversely, Medicare Advantage plans have an annual out-of-pocket maximum for covered Medicare medical services, while Original Medicare alone does not. The medical maximum is not the same as the Part D prescription drug out-of-pocket threshold.

The $0-premium trap

Some Medicare Advantage plans advertise a $0 additional plan premium. For most members this does not eliminate the separate Medicare Part B premium, and it does not erase copays, coinsurance, deductibles or the plan’s annual medical out-of-pocket limit. A plan’s extra dental, vision, hearing or wellness benefits may be useful, but ask about dollar caps, eligible providers, frequency limits and conditions for each advertised extra.

Step-by-step: how to compare Medicare plans using Medicare.gov

1. Step 1 — Collect what matters: your ZIP code, current plan name, Medicare card if logging in, complete medication list with exact strength and quantity, favorite pharmacies, doctors, specialists, hospitals and expected treatments.
2. Step 2 — Open the official Medicare Plan Finder. Select 2027 for the coverage year and enter your ZIP code. You may browse without an account, but logging in can retrieve saved drugs, pharmacies and coverage details.
3. Step 3 — Choose the coverage you are comparing. Do not compare a drug-only plan as if it were a complete health plan. Filter results based on your current coverage and eligibility.
4. Step 4 — Enter every recurring prescription exactly. Include brand or generic, dosage, quantity, frequency and preferred pharmacies. Review the estimated annual drug costs—not only the premium.
5. Step 5 — Check provider participation yourself. Use plan directories as a starting point, then call your providers and the plan to verify the specific plan network and 2027 status.
6. Step 6 — Inspect detailed costs and coverage rules. Consider total premiums, annual deductibles, copays, coinsurance, drugs, out-of-pocket limits, referrals, prior authorization and travel.
7. Step 7 — Check quality information. Review the 2027 Medicare Star Ratings, but do not use stars as a substitute for prescription coverage, medical access or affordability.
8. Step 8 — Save a shortlist, call for clarification, and enroll only after confirming details. Record the submission date, confirmation number, the exact plan name and requested effective date.

Medicare itself recommends checking covered prescriptions, physicians, pharmacies, medical services and annual costs, and reminds users that free, impartial State Health Insurance Assistance Program (SHIP) counseling is available. SHIPs are not insurance companies and do not sell plans. You can also enroll on Medicare.gov, contact the chosen plan or call 1-800-MEDICARE (1-800-633-4227); TTY: 1-877-486-2048.

Compare the total yearly cost—not just monthly premiums

A low premium is appealing because it is easy to see. But the more meaningful question is: What might this plan cost me for the care I actually use, and what happens if I have an unexpectedly expensive medical year? Consider both routine spending and financial exposure during a serious illness.

Illustrative annual spending = 12 × monthly premiums + expected doctor and hospital cost sharing + eligible prescription out-of-pocket costs + other covered cost sharing. Compare separately the plan’s maximum out-of-pocket exposure for covered medical services and the Part D drug threshold. Do not assume all spending counts toward either limit.

Check whether the Part B premium, a separate Part D premium, a stand-alone Medigap premium, income-related adjustments or costs outside the plan’s covered benefits apply in your situation. Some costs do not count toward the annual medical maximum, including monthly premiums, and a provider who is out of network may be treated very differently. The Medicare coverage comparison explains these distinctions.

These numbers are hypothetical arithmetic examples, not quotes for any actual Medicare plan. With four specialist visits and no other spending, Plan A appears cheaper by $320 on those line items alone. But the conclusion can flip if one plan has much worse hospital charges, different drug costs or excludes the specialist entirely. The purpose of a comparison is to expose such trade-offs before you switch—not to rank real plans without a ZIP code and personal details.

Estimate the cost in both a normal year and a bad year

A reasonable exercise is to build two columns. In a routine year, include recurring appointments and prescriptions. In an expensive year, consider inpatient admission, repeated specialist treatment, outpatient procedures or rehabilitation. Consult a plan’s Evidence of Coverage for the relevant copays and coverage limits. An annual medical out-of-pocket maximum can help frame worst-case covered medical expense, but it is not necessarily a cap on every health-related bill.

2027 Medicare Part D: the numbers you should actually know

The official Medicare guidance lists a $2,400 annual out-of-pocket threshold in 2027 for covered Part D prescriptions, up from $2,100 in 2026. The maximum Part D deductible is $700 for 2027, although some plans have smaller deductibles or no deductible. These numbers are policy parameters; your medication availability, coverage rules, pharmacies and estimated spending still depend on the specific plan. See Medicare’s updated Part D costs and coverage stages.

The 2027 $2,400 limit includes qualifying Part D out-of-pocket spending, including certain payments made on a beneficiary’s behalf; it is not a universal ceiling on the retail prices of every prescription, on Part B-covered drugs, or on drug-plan premiums. The deductible is also not an additional universal fee that everyone must pay: a plan may have no deductible and different copayment rules. Confirm the exact interpretation on Medicare.gov and the plan’s Evidence of Coverage.

Check all five drug details, not just “covered”

• Exact medicine: same active ingredient, brand or generic, strength and formulation—not simply a similar-sounding drug.
• Cost-sharing tier: preferred generic versus non-preferred or specialty drug tiers can change your annual estimate.
• Prior authorization: some drugs require the plan to approve coverage based on rules and medical information.
• Step therapy and quantity limits: a plan may require another drug first or limit the amount dispensed; exceptions sometimes exist.
• Pharmacy arrangement: preferred retail network, standard network and mail order may have different costs and access.

Plan formulary rules matter especially for people taking insulin, anticoagulants, biologics, medications for chronic conditions or any medicine where switching could be medically difficult. Never stop or change prescribed treatment solely to qualify for an insurance plan. Ask a clinician and the plan about covered alternatives or exception requests. For the details, read Medicare’s official Part D drug-plan rules.

The Medicare Prescription Payment Plan is not a discount program

All Medicare drug plans offer a voluntary option to spread qualifying prescription drug out-of-pocket payments across the calendar year. That arrangement may help someone facing large pharmacy bills early in the year. However, it does not reduce the total drug cost or replace the Part D out-of-pocket limit. Monthly bills can vary, and you still owe applicable plan premiums. Medicare explains when the option may be useful at Medicare Prescription Payment Plan.

Before you change Medicare Advantage, verify doctors, hospitals and referrals

Finding a doctor’s name in an online directory is not enough. Networks change, providers can participate at some locations but not others, and a doctor may accept Original Medicare yet decline a particular Medicare Advantage HMO. To avoid an expensive surprise, verify each clinician’s participation in the exact 2027 plan ID and network, not just the insurer brand. For surgery or cancer care, also check the hospital, surgeon, anesthesiology group, imaging facility and any other key participating providers.

HMO, PPO and travel questions

An HMO commonly centers on in-network care outside emergencies and other exceptions, with referral requirements depending on the plan. A PPO may permit non-emergency out-of-network care but charge more. Travelers and people splitting the year between two states should check non-emergency coverage and service-area rules, not assume that a familiar national insurer brand guarantees national access. Medicare provides a side-by-side guide to Medicare Advantage plan types.

• Will my primary care doctor and every ongoing specialist accept this exact 2027 plan?
• Does my hospital or cancer center participate, including the location I actually use?
• Are referrals or prior authorizations required for planned imaging, physical therapy, surgery or specialty care?
• What happens for an out-of-state urgent visit, routine follow-up or long seasonal stay?
• Is there a separate out-of-network annual medical cost limit for the plan?

Do not overlook the Medigap problem when leaving Medicare Advantage

This is one of the most consequential switching mistakes. If you move from Medicare Advantage back to Original Medicare, you may want a Medigap policy to help pay some Medicare deductibles and coinsurance. But annual Medicare Open Enrollment is not a guaranteed nationwide right to buy Medigap without medical underwriting. Your eligibility for guaranteed-issue rights depends on circumstances, timing and state law.

Medicare cautions that people switching Medigap policies later may face higher premiums, medical questions or a refusal outside protected windows, and certain policies may not be obtainable again after cancellation. Before dropping Medicare Advantage or an existing Medigap contract, check Medicare’s switch/drop guidance and rules for buying a Medigap policy; speak to SHIP or your state insurance department about state-specific protections. Do not assume that because enrollment in Original Medicare is allowed, a desired supplement is automatically approved.

Check employer, union, VA, TRICARE or Medicaid coverage before moving

Coverage from a current or former employer, union, the VA, TRICARE, or Medicaid can coordinate with Medicare in different ways. A seemingly simple Part D or Medicare Advantage enrollment may affect other benefits or access. Contact the plan or benefits administrator first; document their explanation. If your existing drug coverage is “creditable,” keep the annual notice because it can help establish that you are not subject to a Part D late-enrollment penalty later. See Medicare’s definition of creditable drug coverage.

Star Ratings help—but cannot decide the plan for you

CMS publishes Medicare Advantage and Part D quality ratings on a scale of one to five stars. The 2027 ratings were posted in Medicare Plan Finder on October 8, 2026. Quality measures cover aspects of clinical care, member experience, medication use, complaints and administration, depending on the kind of plan. The ratings can be a helpful signal when comparing otherwise suitable choices, but a higher star rating does not guarantee that your doctor is in the network or that your exact medication will be low-cost.

Read the official CMS 2027 Star Ratings fact sheet to understand what the ratings measure. If two plans have similar practical coverage and projected costs, quality and customer-service evidence may help distinguish them. Avoid choosing solely by star score or by a dramatic “five-star” marketing banner.

Use the Annual Notice of Change and Evidence of Coverage

Members should receive an Annual Notice of Change (ANOC) in the fall, normally in September. The ANOC calls out changes for the coming year—for example premiums, deductibles, copays, covered benefits or other plan rules. The Evidence of Coverage (EOC) provides broader contract details about what the plan covers and how costs work. Both documents deserve a focused check even if you plan to stay with the same insurer.

• Mark every changed premium, deductible, copayment, coinsurance rate and maximum out-of-pocket amount.
• Review your prescription formulary and the drug tier for each medicine you take.
• Find out whether your doctor or hospital has indicated any upcoming network change.
• Check whether transportation, dental, hearing, vision and other extra benefits have new limits.
• Note any notice that your plan is being discontinued, merged or will no longer serve your county.
• Call your plan if documents are missing rather than assuming no change means everything remains identical.

The government explains the Annual Notice of Change and Evidence of Coverage separately. If the plan is ending or leaving your area, an additional Special Enrollment Period may apply; do not rely only on generic annual dates without reading your official notice.

Ten common Medicare Open Enrollment mistakes to avoid

• 1. Selecting the lowest premium without an annual cost estimate. A cheap premium may coexist with high drug and specialist charges.
• 2. Confusing 2026 benefits with 2027 benefits. A familiar plan name does not guarantee identical coverage next year.
• 3. Assuming every doctor who accepts Medicare is in Medicare Advantage networks. Confirm the exact plan and location.
• 4. Checking whether a drug is listed, but not its tier, quantity limit, prior authorization or pharmacy. These details drive real spending and access.
• 5. Treating the Part D $2,400 limit as a cap on all medical costs. Prescription spending and Medicare Advantage medical spending use different rules.
• 6. Switching out of Medicare Advantage without checking Medigap eligibility. Purchasing a supplement later may be restricted or more expensive.
• 7. Dropping creditable prescription coverage carelessly. A 63-day or longer gap can trigger a Part D late-enrollment penalty in applicable cases.
• 8. Joining a separate Part D plan without checking interaction with Medicare Advantage. In many HMO/PPO arrangements, this can cause disenrollment from Medicare Advantage.
• 9. Believing January–March is a general second Open Enrollment for everyone. The Medicare Advantage Open Enrollment Period has narrower rules.
• 10. Trusting unsolicited calls or offers of cash to sign up. Use Medicare.gov, verified plan channels or independent SHIP counseling.

One additional mistake is rushing a last-day application without confirming the new policy is appropriate and keeping proof of submission. Switching is not necessarily reversible at any moment; the rules depend on enrollment period and circumstance. Read how Medicare drug-plan switching works before manually cancelling coverage while waiting for the new plan. In an ordinary switch, your old drug coverage generally ends when the new coverage begins—do not create a preventable gap.

Three real-life comparison situations (with invented plan costs)

Case 1: a healthy retiree attracted by a $0 premium

A person who sees a primary doctor twice a year and has no expensive medications may find a low-premium plan attractive. But even for someone currently healthy, there are useful checks: the local hospital network, imaging fees, preventive versus diagnostic service coverage, emergency costs and the worst-case annual medical out-of-pocket amount. A $0 premium does not make these questions irrelevant. The correct comparison uses the person’s budget and risk tolerance rather than an expectation that nothing unexpected will happen.

Case 2: someone taking six maintenance prescriptions

Another person pays $18 per month for a stand-alone Part D plan but spends $960 over the year on covered prescriptions. A competing illustrative plan costs $33 per month and estimates $360 in prescription spending for that person’s actual drug list. On these fictional figures, the first totals $1,176 in annual premium plus drug spending (12 × $18 + $960), while the second totals $756 (12 × $33 + $360), a difference of $420 in favor of the higher-premium plan. All else equal, the lower total matters—but the medicine list and pharmacy must be verified because estimates change.

Case 3: someone planning a procedure in January

A patient expecting an orthopedic operation, cancer treatment or a specialist evaluation shortly after January 1 needs to confirm participating providers, preauthorization requirements, facility charges, follow-up services and transition-of-care provisions. The risk of losing continuity of care may outweigh an attractive premium. Ask the current and prospective plan for written information relevant to the planned treatment, and coordinate with the clinician before switching. Do not cancel or delay medical treatment based solely on marketing material.

What if your health or drug costs are unaffordable?

Someone with limited income and resources may qualify for Extra Help with Medicare Part D costs, or for state Medicare Savings Programs. Medicare’s 2027 Extra Help information includes reduced plan costs and capped copayments for eligible people, but eligibility depends on individual circumstances. Rather than assuming a discount automatically applies, check Medicare’s Extra Help overview or contact SHIP for free application guidance.

If you have both Medicare and Medicaid, or a qualifying chronic condition, a Special Needs Plan (SNP) may be relevant in some locations. Such plans have eligibility rules, specialized networks and coverage arrangements; they are not available everywhere and may not be right for every person. Verify whether a proposed plan coordinates Medicaid correctly and meets the person’s care needs before enrolling. See Medicare’s Special Needs Plans information.

How to submit enrollment safely and verify that the change worked

1. Use Medicare.gov/plan-compare, a verified plan contact, or 1-800-MEDICARE. Be cautious when ads redirect to unrelated “Medicare enrollment” domains.
2. Check the exact insurer, contract/plan name, 2027 coverage year and the requested January 1 effective date before submitting.
3. Never pay an unsolicited caller to “unlock” Medicare enrollment. Genuine plans are subject to official marketing and sales restrictions.
4. Save your enrollment confirmation and look for a welcome letter or card. Contact the plan or Medicare promptly if the expected confirmation does not arrive.
5. At the start of 2027, verify the first prescription claim and ensure your doctors are billing the correct coverage. Report errors early.

Medicare’s marketing rules restrict unsolicited approaches and improper inducements, and the fraud guidance advises people to protect their Medicare and Social Security numbers. Suspicious calls asking for a card number or threatening immediate cancellation are a red flag. If a plan or representative misled you, contact 1-800-MEDICARE; a case-specific Special Enrollment Period may sometimes be available.

What if you miss December 7, 2026?

Your opportunities depend on the coverage you have and your circumstances. If you are already enrolled in Medicare Advantage, the January 1–March 31, 2027 Medicare Advantage Open Enrollment Period generally permits one allowed change, such as moving to another Medicare Advantage plan or returning to Original Medicare (with an opportunity to join a stand-alone drug plan). It does not generally let a person who is already in Original Medicare arbitrarily switch stand-alone Part D plans outside the regular dates.

Some people qualify for a Special Enrollment Period because they move, lose certain coverage, have a plan contract end, qualify for certain assistance programs, or experience other qualifying events. The type and duration of the opportunity vary. Use Medicare’s official Special Enrollment Period rules or call 1-800-MEDICARE to check a specific situation. Do not assume you are permanently stuck or automatically eligible without confirming the applicable rule.

A printable comparison worksheet before you choose

Fill this worksheet with details from the actual 2027 plans rather than generic internet lists. Take a copy to a free SHIP counseling session if you need help with comparisons. A good decision is one you can explain: which doctors and medicines are covered, why the estimated annual cost is acceptable, and what financial and care-access trade-offs you are accepting.

Final takeaway: compare care, drugs and risk before price

The 2026 Medicare Open Enrollment window is October 15 through December 7 for changes taking effect in 2027. A careful review should start with your personal medication list and physicians, examine annual spending and a serious-illness scenario, and consider the rights you may lose when changing coverage arrangements. The 2027 Part D out-of-pocket threshold is $2,400 for eligible covered drug spending—but it is not a substitute for checking the rest of your costs.

If you take just one action, use the official Medicare Plan Finder to compare your 2027 options, read your ANOC, then verify the details with your plan and clinicians. There is no single “best Medicare plan” for everyone; there is a plan whose costs, rules and access match the individual’s needs more closely than the alternatives. When uncertain, free, independent SHIP counseling or 1-800-MEDICARE can help clarify the rules before you commit.

Official sources and further reading

• Medicare — Open Enrollment dates and allowed changes — official election period and January 1 effective date.
• Medicare — 2027 Plan Finder — compare actual plans for your ZIP code and medications.
• Medicare — Original Medicare versus Medicare Advantage — provider access, costs, supplemental coverage and restrictions.
• Medicare — Annual Notice of Change — what to review in the fall mailing.
• Medicare — Evidence of Coverage — detailed plan benefits and rules.
• Medicare — Part D costs and coverage stages — 2027 $2,400 threshold and $700 maximum deductible.
• Medicare — Part D drug plan rules — formularies, prior authorization, step therapy and quantity limits.
• CMS — 2027 Medicare Star Ratings — official 2027 quality publication.
• Medicare — Prescription Payment Plan — optional monthly spreading of prescription costs.
• Medicare — Switching or dropping a Medigap policy — protected rights and caution about re-enrollment.
• Medicare — Special Enrollment Periods — limited opportunities outside normal dates.
• Medicare — Extra Help with Part D costs — financial assistance for eligible beneficiaries.
• Medicare — Plan marketing rules — avoiding inappropriate selling tactics.
• Medicare — Talk to someone / SHIP counseling — impartial help and Medicare phone contact.
• CMS — Medicare Advantage and Part D plans in 2027 — public national-level premiums and plan-market context; averages do not predict individual costs.