Medicare Open Enrollment 2027: How to Compare Plans, Change Coverage and Understand ACA Deadlines

These are separate insurance systems.

If you already have Medicare, the ACA Marketplace normally is not an alternative Medicare shopping platform. Medicare.gov says people with Medicare do not need Marketplace coverage, and federal rules generally prohibit knowingly selling a Marketplace plan to someone who already has Medicare.

That makes understanding which enrollment period applies to you the first—and most important—step.

Medicare and ACA Open Enrollment 2027: Important Dates

Medicare dates are nationwide federal enrollment dates. HealthCare.gov uses the November 1–January 15 schedule, although residents of states operating their own Marketplace should confirm deadlines with their state exchange.

What Is Medicare Open Enrollment?

Medicare Open Enrollment is the annual opportunity for people already eligible for Medicare to review or change their Medicare health and prescription-drug coverage.

Between October 15 and December 7, Medicare says eligible beneficiaries may:

• switch from one Medicare Advantage plan to another;
• switch from Original Medicare to Medicare Advantage;
• leave Medicare Advantage and return to Original Medicare;
• join, drop or switch a stand-alone Medicare Part D prescription-drug plan when eligible;
• change Medicare Advantage drug coverage.

Changes submitted by the December 7 deadline generally begin January 1.

You do not necessarily need to change plans every year.

But reviewing your coverage can still be worthwhile because premiums, deductibles, formularies, provider networks, copayments and supplemental benefits can change annually.

Medicare plans send current members an Annual Notice of Change, or ANOC, each fall explaining changes that will take effect in January. Medicare advises beneficiaries to review that document before deciding whether their existing plan still meets their needs.

Why You Should Not Automatically Keep the Same Medicare Plan

Automatic renewal may be convenient, but last year's plan is not automatically the best option for the next year.

A plan could change:

• its prescription-drug formulary;
• drug tiers;
• pharmacy network;
• doctor or hospital network;
• specialist copayments;
• deductibles;
• monthly premium;
• prior-authorization requirements;
• out-of-pocket limit;
• dental, vision or hearing benefits.

Your own circumstances may have changed as well.

You may have started a new prescription, developed a condition requiring specialist care, moved, changed pharmacies or begun seeing a doctor who is not in your current plan's network.

The right question is therefore not simply:

“Did my premium increase?”

A better question is:

“What will this plan probably cost me in total for the care and prescriptions I expect to use?”

How to Choose a Medicare Plan for 2027: Step by Step

Step 1: Read Your Annual Notice of Change

If you already have Medicare Advantage or Part D coverage, begin with the ANOC sent by your existing plan.

Look specifically for changes involving:

• monthly premiums;
• medical deductibles;
• prescription-drug deductibles;
• copays and coinsurance;
• drug formularies;
• pharmacy networks;
• provider networks;
• maximum out-of-pocket limits;
• supplemental benefits.

Medicare says beneficiaries normally receive the Annual Notice of Change in September.

Do not assume that a benefit advertised prominently this year will remain identical next year.

Step 2: Decide Between Original Medicare and Medicare Advantage

There are two primary ways to receive Medicare coverage.

Original Medicare

Original Medicare includes Part A and Part B.

Medicare says beneficiaries generally may use any doctor or hospital in the United States that accepts Medicare. Prescription-drug coverage normally requires a separate Part D plan, and some people buy Medicare Supplement Insurance, or Medigap, to help with eligible out-of-pocket costs.

Medicare Advantage

Medicare Advantage, also called Part C, is provided through Medicare-approved private insurers.

Plans may combine hospital, medical and prescription-drug coverage and can include additional benefits.

However, provider networks, referrals and prior authorization can matter considerably depending on the specific plan. Medicare notes that some Medicare Advantage plans generally require members to obtain non-emergency care from network providers, while PPOs may permit out-of-network care at a higher cost.

Neither system is automatically better for every beneficiary.

Your doctors, prescriptions, expected medical usage, travel patterns, finances and preference for provider flexibility should influence the decision.

Step 3: Make a Complete Prescription List

Before using Medicare Plan Compare, prepare an updated list containing:

• exact drug name;
• dose;
• frequency;
• preferred pharmacy;
• alternative pharmacies you could use.

Medicare's Plan Compare system can use your prescriptions and pharmacy information to estimate annual drug costs under available plans.

This is especially important because comparing plans by premium alone can produce a misleading result.

A plan charging a low premium could still become expensive if one of your regular medications is placed on a high-cost tier or is not included on the formulary.

Step 4: Check Every Important Doctor and Hospital

If considering Medicare Advantage, verify whether your:

• primary-care physician;
• cardiologist;
• oncologist;
• orthopedic specialist;
• mental-health professional;
• preferred hospital;
• rehabilitation provider;
• pharmacy

will participate in the plan in 2027.

Medicare specifically recommends asking doctors and pharmacies whether they participate in the plan's network before enrolling.

Do not rely only on an old provider directory.

It can be sensible to confirm participation with both the insurer and the medical practice before making a consequential switch.

Step 5: Compare Total Cost, Not Just the Premium

A "$0 premium" Medicare Advantage plan does not mean medical care is free.

Depending on the plan, you may still face:

• the Medicare Part B premium;
• deductibles;
• specialist copays;
• hospital copays;
• coinsurance;
• prescription expenses;
• out-of-network charges where applicable.

Medicare says beneficiaries considering health plans should evaluate monthly premiums, deductibles, copayments and the plan's annual medical out-of-pocket limit.

A plan with a slightly higher monthly premium could potentially cost less overall for someone who expects regular specialist visits or expensive prescriptions.

Conversely, someone with limited medical use may value a different cost structure.

Step 6: Check the Maximum Out-of-Pocket Exposure

For Medicare Advantage, pay close attention to the plan's annual medical out-of-pocket maximum.

This figure can matter more than a dental allowance, grocery benefit or another heavily advertised extra benefit if you require substantial care during the year.

Ask:

“What is the most I could potentially pay for covered medical services if I become seriously ill?”

Then compare that figure across your shortlisted plans.

Step 7: Examine Prescription Costs Carefully

Prescription coverage deserves a separate calculation from medical coverage.

For 2027, CMS projects the average monthly premium for a stand-alone Part D plan at approximately $36, up by less than $1 from the 2026 projected average cited by CMS. The actual premium a beneficiary pays depends on the individual plan and, for some beneficiaries, income-related charges.

CMS has also set the 2027 standard Part D deductible at $700 and the annual Part D out-of-pocket threshold at $2,400 under the defined standard benefit.

Those national parameters do not eliminate the need to compare individual formularies.

The cost of your exact medications under a particular plan remains one of the most important variables.

Step 8: Do Not Pick a Plan Only for Dental, Vision or Grocery Benefits

Additional Medicare Advantage benefits can be valuable.

But they should generally come after the essentials:

1. Are your doctors covered?
2. Are your hospitals covered?
3. Are your drugs covered?
4. What is your likely annual cost?
5. What is the medical out-of-pocket maximum?
6. Are referrals or prior authorizations likely to affect your care?

Only after answering those questions should supplemental benefits become a major deciding factor.

What Are the Best Medicare Advantage Plans for 2027?

There is no single Medicare Advantage plan that can accurately be called the best plan for everyone in the United States.

Medicare Advantage availability is geographically specific, and personal requirements differ substantially.

One person may prioritize a particular cancer center.

Another may need an expensive specialty drug.

Someone who spends part of each year in another state may need greater provider flexibility.

Another beneficiary may mainly want predictable local costs.

CMS says more than 99% of Medicare beneficiaries are expected to have access to at least one Medicare Advantage plan for 2027, and 97% are expected to have access to 10 or more options. The weighted average monthly Medicare Advantage premium is projected at about $12 for 2027, down from $14.37 in 2026. Those are national averages and do not describe the premium, network or benefits of a specific local plan.

So a safer interpretation of the popular search phrase “best Medicare Advantage plans 2027” is:

Which plan offers the best combination of doctors, prescriptions, total costs and coverage rules for your specific circumstances?

How to Change a Medicare Plan

The official Medicare process is relatively straightforward.

During Open Enrollment:

1. Review your current coverage and ANOC.
2. Use Medicare Plan Compare to see plans available for your ZIP code.
3. Enter your prescriptions and pharmacies.
4. Compare estimated costs and plan details.
5. Verify doctors and hospitals.
6. Select the plan you want.
7. Enroll before December 7.

You can enroll through Medicare's Plan Compare system, directly through the plan, or by calling Medicare. Medicare's official number is 1-800-MEDICARE (1-800-633-4227).

Be Careful Before Leaving Medicare Advantage for Original Medicare

This is one of the most important enrollment warnings.

Leaving Medicare Advantage for Original Medicare does not automatically mean you will have unrestricted access to a new Medigap policy on favorable terms.

Under federal rules, your strongest Medigap enrollment protections generally apply during specified enrollment periods and guaranteed-issue situations. Outside those circumstances, an insurer may in some states use medical underwriting, charge more or deny an application. States can provide broader protections.

For that reason, someone considering a move from Medicare Advantage to Original Medicare who expects to use Medigap should investigate Medigap eligibility before finalizing the switch.

Medicare itself warns that there are limits on when Medigap can be added.

Free Medicare Counseling Is Available

You do not necessarily need to rely on an insurance salesperson to understand your choices.

Medicare recommends the State Health Insurance Assistance Program, or SHIP, which provides free personalized Medicare counseling and is not connected to an insurance company or health plan.

This can be particularly useful when comparing:

• Original Medicare and Medicare Advantage;
• Part D plans;
• Medigap implications;
• Extra Help;
• employer or retiree coverage.

Medicare Advantage Open Enrollment Is Different

There is another Medicare enrollment period from January 1 through March 31.

The Medicare Advantage Open Enrollment Period is only for people already enrolled in Medicare Advantage.

During that period, eligible beneficiaries can generally make one change by:

• switching to another Medicare Advantage plan; or
• leaving Medicare Advantage for Original Medicare and, when eligible, adding a stand-alone Part D plan.

It is not a general second Open Enrollment period for everyone with Medicare.

ACA Marketplace Open Enrollment for 2027

For people who are not using Medicare and need individual or family health insurance, the ACA Marketplace has its own enrollment period.

On HealthCare.gov:

November 1, 2026: 2027 Open Enrollment begins.

December 15, 2026: Deadline to enroll or change plans for coverage beginning January 1.

January 1, 2027: Coverage begins for eligible consumers who selected a plan by December 15 and paid the required first premium.

January 15, 2027: Open Enrollment ends.

February 1, 2027: Coverage generally begins for people selecting plans from December 16 through January 15 after paying the first premium.

Outside Open Enrollment, people generally need a qualifying life event for a Special Enrollment Period, while Medicaid and CHIP enrollment can remain available throughout the year for eligible applicants.

How to Choose an ACA Marketplace Plan for 2027

1. Update Your Expected 2027 Income

Marketplace premium tax credits depend on household and expected income information supplied in the application.

HealthCare.gov warns that failing to update income and household information could result in receiving too much or too little assistance.

Do not simply reuse an outdated income estimate if your circumstances have changed.

2. Check Your 2027 Subsidy Before Comparing Premiums

HealthCare.gov says pandemic-era additional Marketplace savings ended on December 31, 2025. It currently advises consumers that 2027 income levels and savings information will become available around November 1.

That means an enrollee should not assume that the subsidy or net premium they paid in an earlier year will remain identical in 2027.

The official Marketplace application determines the amount of premium tax credit, if any, based on eligibility and current household information.

3. Compare the Net Premium

The advertised premium is only one number.

What matters for many Marketplace consumers is the monthly premium after any eligible premium tax credit.

Premium tax credits are available only through the Marketplace or approved enrollment pathways connected to it.

4. Compare Deductibles

A very low monthly premium can come with a high deductible.

Consider how much care you realistically expect to use.

People anticipating frequent medical visits, testing, therapy or procedures may value a plan with a different balance between premiums and cost sharing than someone primarily seeking protection from major unexpected expenses.

5. Check the Out-of-Pocket Maximum

For 2027 Marketplace plans, HealthCare.gov lists the maximum permitted annual out-of-pocket limit at $12,000 for individual coverage and $24,000 for family coverage.

Plans can have lower limits. The limit generally applies to covered in-network services and does not include premiums, non-covered services or many out-of-network expenses.

For consumers worried about the financial effect of a major illness or hospitalization, this number can be as important as the monthly premium.

6. Understand Bronze, Silver, Gold and Platinum

Marketplace metal categories describe how costs are divided between the enrollee and insurer.

They do not represent the quality of doctors or medical care.

HealthCare.gov divides Marketplace plans into Bronze, Silver, Gold and Platinum categories. Generally, a lower-premium tier can involve greater cost sharing when services are used, while higher-premium tiers can shift more costs to the insurer.

There is one particularly important Silver-plan rule.

If your income qualifies you for cost-sharing reductions, you must choose an eligible Silver plan to receive those additional reductions in deductibles, copayments and coinsurance.

7. Check Doctors, Hospitals and Prescriptions

Marketplace plans can use HMO, EPO, PPO and other network structures.

HealthCare.gov notes that these models differ in their rules for out-of-network providers, referrals and covered services.

Before enrolling, search the plan's provider network and verify important doctors and hospitals.

Prescription formularies and pharmacy networks should also be checked for medications you use regularly.

Medicare vs ACA Marketplace: Which One Applies to You?

One of the most common enrollment-season mistakes is treating Medicare and the ACA Marketplace as interchangeable insurance systems.

They are not.

If you already have Medicare

Use Medicare enrollment rules and Medicare plan-comparison tools.

You generally should not buy a Marketplace plan to replace or supplement Medicare.

If you do not have Medicare and need individual or family coverage

The Health Insurance Marketplace may be appropriate, depending on eligibility.

If you are approaching Medicare eligibility while using Marketplace coverage

Do not assume Marketplace coverage and subsidies should simply continue unchanged.

Coordinate the transition carefully so you understand Medicare enrollment dates, Marketplace termination timing and any consequences of delaying Medicare.

Quick Medicare 2027 Enrollment Checklist

Before December 7, Medicare beneficiaries should ideally know:

• whether their existing plan is continuing;
• the new 2027 premium;
• the deductible;
• whether every important medication remains covered;
• the expected annual prescription cost;
• whether preferred pharmacies changed;
• whether their doctors remain in-network;
• whether their preferred hospital remains in-network;
• specialist and hospital copayments;
• prior-authorization requirements;
• the medical out-of-pocket maximum;
• whether moving to Original Medicare could affect Medigap eligibility.

Do not choose purely because of an advertisement, a "$0 premium" message or a supplemental benefit that you may rarely use.

Quick ACA 2027 Enrollment Checklist

Before choosing a Marketplace plan:

• update your estimated 2027 household income;
• update household members;
• calculate your actual premium after subsidies;
• compare deductibles;
• compare copays and coinsurance;
• compare annual out-of-pocket limits;
• verify doctors and hospitals;
• check prescription coverage;
• see whether you qualify for cost-sharing reductions;
• compare Silver plans carefully if you qualify for those reductions;
• enroll by December 15 if you want coverage beginning January 1;
• pay the first premium required by the insurer.

HealthCare.gov says existing members should actively update and compare their coverage even when automatic re-enrollment is available because plans, prices and personal circumstances can change.

Is the Cheapest Health Plan Usually the Best?

Not necessarily.

The cheapest premium can be attractive, but insurance should be evaluated by total expected financial exposure.

Consider:

Annual premium + expected deductible spending + copays + coinsurance + prescription costs + realistic network-related expenses.

Also examine the maximum amount you could face in a medically difficult year.

A person requiring regular specialist visits may reach a different conclusion than someone who rarely needs medical care.

This is why neither Medicare.gov nor HealthCare.gov recommends selecting coverage based on premium alone. Both direct consumers to compare costs, networks, medications and benefits.

Be Careful With Enrollment Scams and Sales Pressure

Enrollment season also brings heavy insurance marketing.

Consumers should be cautious about unsolicited callers asking for:

• Medicare numbers;
• Social Security numbers;
• bank details;
• payment information;
• account passwords.

You do not need to make an immediate insurance decision because an unsolicited caller says an offer is expiring.

For Medicare decisions, use Medicare.gov, 1-800-MEDICARE or SHIP.

For federal Marketplace coverage, use HealthCare.gov or an officially recognized enrollment channel.

Bottom Line

The 2027 enrollment season begins first for Medicare.

Medicare Open Enrollment: October 15–December 7, 2026.

HealthCare.gov Marketplace Open Enrollment: November 1, 2026–January 15, 2027.

The most important strategy for either program is the same: do not judge health insurance by the monthly premium alone.

For Medicare, compare prescriptions, providers, total expected cost, plan rules and maximum medical exposure.

For ACA Marketplace coverage, update household and income information, calculate the premium after any eligible assistance, compare deductibles and out-of-pocket limits, and confirm that doctors and medications are covered.

And remember that Medicare and Marketplace coverage are different systems. Someone already enrolled in Medicare normally should not use the ACA Marketplace as a replacement shopping option.

For a decision affecting major medical needs, medications or a switch between Medicare Advantage and Original Medicare, beneficiaries may also want independent help from Medicare, SHIP or an appropriate licensed professional familiar with their individual circumstances.

Frequently Asked Questions

When is Medicare Open Enrollment for 2027?

Medicare Open Enrollment runs from October 15 through December 7, 2026. Most coverage changes made during this period take effect January 1, 2027.

How do I change my Medicare plan for 2027?

Use Medicare Plan Compare to review local options, enter your prescriptions and pharmacies, verify providers, compare estimated annual costs and enroll in the selected plan before December 7. Medicare also allows enrollment through plans directly or through 1-800-MEDICARE.

What is the best Medicare Advantage plan for 2027?

There is no universally best Medicare Advantage plan. The right choice depends on your ZIP code, doctors, hospitals, medications, medical needs, finances and preferred plan structure.

Can I switch from Medicare Advantage to Original Medicare?

Yes, Medicare Open Enrollment allows a switch from Medicare Advantage to Original Medicare. However, investigate Medigap eligibility carefully because federal law does not guarantee access to a new Medigap policy in every situation.

What is the average Medicare Advantage premium for 2027?

CMS projects a weighted average monthly Medicare Advantage premium of approximately $12 in 2027, compared with $14.37 in 2026. Individual plan premiums vary considerably and Medicare beneficiaries generally must continue paying the applicable Part B premium.

What is the Medicare Part D out-of-pocket threshold for 2027?

CMS has set the 2027 defined standard Part D out-of-pocket threshold at $2,400, with a standard deductible of $700.

When does ACA Open Enrollment start for 2027?

HealthCare.gov Open Enrollment begins November 1, 2026.

What is the ACA enrollment deadline for 2027?

On HealthCare.gov, December 15 is the deadline for coverage beginning January 1. Open Enrollment continues through January 15, with coverage generally beginning February 1 for selections made after December 15.

Can I have Medicare and an ACA Marketplace plan?

Medicare.gov says people who already have Medicare do not need Marketplace coverage, and it is generally illegal to knowingly sell a Marketplace plan to someone who has Medicare.

Should I automatically renew my ACA plan?

Automatic re-enrollment may prevent a coverage gap, but HealthCare.gov recommends updating household and income information and comparing available plans because costs and coverage can change.

Do Marketplace premium subsidies continue in 2027?

Premium tax credits continue for qualifying Marketplace consumers under current rules, but eligibility depends on household and income information. HealthCare.gov says the additional pandemic-era savings ended in 2025 and that updated 2027 savings information is expected around November 1.

Bottom Line

Medicare Open Enrollment for 2027 runs October 15–December 7, 2026. ACA Marketplace Open Enrollment starts November 1. Compare total costs, doctors, drugs and out-of-pocket limits—not just premiums—before changing coverage.

Key Takeaway

Medicare: Oct 15–Dec 7.

ACA Marketplace: Nov 1–Jan 15.

Compare total cost, not premium.

Medicare ≠ Marketplace.

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