You are now leaving and will continue to shop for Medicare plans with our partner, eHealth, a non-government website. ehealth

Medicare Open Enrollment 2021 Guide

Everything you need to know about this year's enrollment dates, coverage costs, eligibility details and opportunities to change coverage

During the annual Medicare open enrollment, Medicare plan enrollees can reevaluate their coverage – whether it’s Original Medicare with supplemental drug coverage, or Medicare Advantage – and make changes if they want to do so. | Image: rocketclips /

Medicare open enrollment for 2021 coverage ended on December 8. Learn how you can change your Medicare coverage outside of the fall open enrollment period.

When is Medicare open enrollment?

Medicare open enrollment – also known as Medicare’s annual election period – runs from October 15 through December 7 each year. During this annual window, Medicare plan enrollees can reevaluate their coverage – whether it’s Original Medicare with supplemental drug coverage, or Medicare Advantage – and make changes or purchase new policies if they want to do so.

During the Medicare open enrollment period, you can:

  • Switch from Original Medicare to Medicare Advantage (as long as you’re enrolled in both Medicare Part A and Part B, and you live in the Medicare Advantage plan’s service area).
  • Switch from Medicare Advantage to Original Medicare (plus a Medicare Part D plan, and possibly a Medigap plan).
  • Switch from one Medicare Advantage plan to another.
  • Switch from one Medicare Part D prescription drug plan to another.
  • Enroll in a Medicare Part D plan if you didn’t enroll when you were first eligible for Medicare. If you haven’t maintained other creditable coverage, a late-enrollment penalty may apply.

Prior to 2021, patients with end-stage renal disease were unable to enroll in Medicare Advantage plans unless there was a Medicare Special Needs plan available in their area for ESRD patients. But that changed as of 2021, under the terms of the 21st Century Cures Act. People with ESRD have the option to enroll in Medicare Advantage for 2021, and CMS expects more than 40,000 to do so. This could be particularly advantageous for beneficiaries with ESRD who are under age 65 and living in states that don’t guarantee access to Medigap plans for people under the age of 65.

Special enrollment period for people in areas affected by weather disasters

Although Medicare’s open enrollment period ends on December 7 each year, extended enrollment opportunities are available to people in areas where FEMA declares an emergency or major disaster that hampered your ability to complete your enrollment during the normal window.

Medicare disaster special enrollment periodCMS has confirmed that the special enrollment period (SEP) in these circumstances continues for four full calendar months after the month that the disaster/emergency incident began, and is applicable for people who live in areas where the incident period began between August 1 and December 7. Enrollments during the special enrollment period are effective the first of the month after you submit your enrollment.

So if you’re eligible for the emergency/disaster SEP and you enroll by December 31, your coverage will take effect January 1, 2021 (ie, the same date it would have taken effect if your area hadn’t been hit with a disaster and you had been able to enroll by December 7).

Some of the SEPs continue past the end of 2020. If the incident began in August, your SEP ends on December 31. But if the incident began in September, your SEP ends on January 31, 2021, if the incident began in October, your SEP ends on February 28, and if the incident began in November (only applicable to counties in Florida affected by Hurricane Eta), your SEP continues through the end of March. In each case, your new coverage will take effect the first of the month after you enroll.

There are some states where FEMA has declared emergency or major disasters statewide, and others where only some counties are affected:

The SEP is available for people who reside in (or resided in at the start of the incident period) one of the affected areas, and for people who rely on Medicare enrollment assistance from a friend or family member who lives in one of the affected areas.

If you’re in one of these areas, you can discuss your eligibility for the SEP with a licensed Medicare advisor at 1-844-309-3504.

Medicare open enrollment: What you can’t do

The annual Medicare open enrollment period does not apply to Medigap plans, which are only guaranteed-issue in most states during a beneficiary’s initial enrollment period, and during limited special enrollment periods.

If you didn’t enroll in Medicare when you were first eligible, you cannot use the fall open enrollment period to enroll. Instead, you’ll use the Medicare general enrollment period, which runs from January 1 to March 31.

Medicare’s general enrollment period is for people who didn’t sign up for Medicare Part B when they were first eligible, and who don’t have access to a Medicare Part B special enrollment period. It’s also for people who have to pay a premium for Medicare Part A and didn’t enroll in Part A when they were first eligible.

If you enroll during the general enrollment period, your coverage will take effect July 1.

Learn more about Medicare’s general enrollment period.

How to change Medicare plans

Once you’re enrolled in Medicare, you’ll have various opportunities to change certain aspects of your coverage. Here’s an overview:

  • During the annual open enrollment period (October 15 – December 7), you can make a variety of changes, none of which involve medical underwriting. (Prior to 2021, people with end-stage renal disease were not able to switch to Medicare Advantage during the open enrollment period, but that’s no longer the case as of 2021.):
    • Switch from Medicare Advantage to Original Medicare or vice versa.
    • Switch from one Medicare Advantage plan to another.
    • Switch from one Part D prescription plan to another. It’s highly recommended that all beneficiaries use Medicare’s plan finder tool each year to compare the available Part D plans, as opposed to simply letting an existing drug plan auto-renew.
    • Join a Medicare Part D plan. (Late-enrollment penalty might apply.)
    • Drop your Part D coverage altogether. (Re-enrolling in a later year will include a late-enrollment penalty if you’re not maintaining other creditable drug coverage.)
  • During the Medicare Advantage open enrollment period (January 1 – March 31), Americans who are already enrolled in Medicare Advantage can:
    • Switch to Original Medicare (and enroll in a Part D plan; access to Medigap might require medical underwriting, depending on the circumstances.)
    • Switch to a different Medicare Advantage plan.
    • Only one plan change is allowed during this window (unlike the fall enrollment period, when a person can change their mind multiple times).
  • During the five-star enrollment period (December 8 – November 30), people who live in an area with a five-star Medicare Part D or Medicare Advantage plan can switch to that plan if they choose to do so.
  • During the first year a person is enrolled in Medicare Advantage, they can switch to (or back to) Original Medicare and a Part D plan. And with some exceptions, they also have guaranteed-issue access to a Medigap plan.
  • Any time during the year, a person enrolled in Original Medicare can apply for a different Medigap plan. But if it’s not during the person’s one-time Medigap enrollment window, the insurer will likely use medical underwriting to determine whether to issue the policy and at what price (note that some states have continuous or annual windows when at least some Medigap plans are guaranteed issue).

Medicare eligibility

For most Americans, Medicare eligibility goes hand in hand with turning 65, but some people become eligible for Medicare earlier. Most Medicare beneficiaries receive Medicare Part A without a monthly premium, but some have to pay for it. And some beneficiaries have to pay more than the standard amount for their Medicare Part B and Part D coverage.

Here’s our detailed overview of eligibility for all parts of Medicare coverage. In summary:

  • Most Americans become eligible for Medicare when they turn 65.
  • But 15 percent of all Medicare beneficiaries are under 65, and became eligible after receiving Social Security disability benefits for two years or being diagnosed with ALS or end-stage renal disease.
  • In order to enroll in Medicare Advantage, you must enroll in both Medicare Part A and Part B. Your Medicare Advantage plan will take the place of both parts, and will likely also include Medicare Part D prescription drug coverage.
  • In order to get Medicare Part A without having to pay a monthly premium, you or your spouse must have worked for at least 10 years in the United States, paying Medicare taxes during that time.
  • If your income is high (defined in 2020 as more than $87,000 for a single person or $174,000 for a couple; increasing to $88,000 and $176,000 in 2021), you’ll pay more than other people for your Part B coverage and your Part D coverage.
  • You’re eligible to enroll in Medicare Part D as long as you have either Medicare Part A or Part B.
  • If you’re enrolled in both Medicare Part A and Part B (but not Medicare Advantage or Medicaid), you’re eligible to enroll in a Medigap plan to supplement your Medicare coverage. You’ll have a six-month guaranteed-issue window during which you can sign up for any Medigap plan available in your area. In most states and most circumstances, you’ll have to go through medical underwriting if you decide to apply for a Medigap plan after that window ends.

How to enroll in Medicare

This section walks you through the basics of enrolling in Medicare. But first you’ll want to read our tips for deciding between Original Medicare plus Medigap and Part D coverage, versus a Medicare Advantage plan.

Enrolling in Original Medicare

If you’re already receiving Social Security or Railroad Retirement Board benefits and you’re a U.S. resident, the federal government automatically enrolls you in both Medicare Part A and Medicare Part B at age 65. You’ll receive your Medicare card in the mail about three months before you turn 65, and your coverage will take effect the first of the month you turn 65.

Medicare Part B has a monthly premium, which will be deducted from your Social Security or Railroad Retirement check. The standard Part B premium is $144.60/month in 2020, and is increasing slightly, to $148.50/month in 2021.

You can opt out of Part B and avoid the premiums, but it’s generally only a good idea to do that if you’ve got health insurance from your current employer or your spouse’s current employer, and the employer has at least 20 employees.

If you are turning 65, but you’re not yet receiving Social Security or Railroad Retirement benefits, you won’t be automatically enrolled in Original Medicare. Instead, you’ll be able to enroll during a seven-month enrollment period that includes the three months before your birth month, the month you turn 65, and the three following months. So if you’ll be 65 on July 14, your open enrollment period will be April through October. You’ll enroll through the Social Security Administration. And although your enrollment window is seven months long, you need to enroll during the three months prior to your birthday month in order to have coverage that takes effect the first of the month that you turn 65. If you enroll during your birthday month or one of the three following months, your coverage effective date will be delayed.

If you’re disabled and receiving Social Security Disability benefits, your Medicare coverage will start automatically in the 25th month that you’re receiving disability benefits. (If you have ALS or end-stage renal disease, you do not have to wait two years to get Medicare.)

Enrolling in Medicare Advantage

To join a Medicare Advantage Plan, you will need to have Original Medicare (Part A and Part B) coverage and live in an area where an Advantage plan is offered. (Most parts of the country have Medicare Advantage plans available, but some rural areas do not.)

A Medicare Advantage plan will wrap your Medicare Part A and Part B (and in most cases, Part D) coverage into one plan. But you’ll still have to pay the government a premium for Part B, in addition to the premium you pay for Medicare Advantage (which may be $0, depending on the plan).

You can enroll in a Medicare Advantage plan when you’re first eligible for Medicare, or during the annual Medicare open enrollment period in the fall (October 15 to December 7).

Enrolling in Medicare Part D

The first opportunity for Medicare Part D enrollment is when you’re initially eligible for Medicare – during the seven-month period beginning three months before the month you turn 65, or during the seven-month period beginning three months before your 25th month of disability. (Eligibility rules are different if a person is enrolling in Medicare due to a diagnosis of ALS or end-stage renal disease.)

In both of these cases – whether you’re turning 65 or are eligible for Medicare because of a disability — you likely have the option of selecting a Medicare Advantage plan that includes Part D prescription drug coverage, and using that in place of Medicare A, B, and D

If you enroll in Medicare during the January – March General Enrollment period, you can enroll in Part D between April 1 and June 30.

If you’re enrolled in a Medicare Advantage plan and use the Medicare Advantage open enrollment period (January 1 to March 31) to switch to Original Medicare, you’ll also have the option to sign up for a Part D plan to supplement your Original Medicare coverage.

Suggested reading: Four signs you need to change your Part D coverage

Suggested reading: Seven rules for shopping Medicare Part D plans

Enrolling in a Medicare Supplement (Medigap)

During your initial Medigap enrollment period (the six months starting with the month you’re at least 65 years old and enrolled in Medicare A and B) you can’t be denied Medigap coverage or be charged more for the coverage because of your medical history.

But after that window ends, Medigap insurers in most states can use medical underwriting to determine your premiums and eligibility for coverage. (New York, Connecticut, Massachusetts, Maine, Missouri, California, Oregon, and Washington have rules making it easier for people to enroll or switch to a new Medigap plan after the initial enrollment period ends. There are also limited federal guaranteed-issue rights for Medigap plans.)

If you’re under 65 and eligible for Medicare because of a disability, there are 33 states that provide some sort of guaranteed issue period during which you can purchase a Medigap plan. But in the majority of those states, the carriers can charge additional premiums for people under 65. You can click on a state on this map to see how Medigap plans are regulated in the state.

To find out about Medigap policies in your state, contact your State Department of Insurance or your State Health Insurance Assistance Program, or call 1-855-593-5633 to speak with one of our partners, who can help you find a plan in your area.

2021 Medicare costs

Each part of Medicare has costs that go along with it, either in the form of premiums, out-of-pocket costs when you need medical care, or both. Here’s a summary of what to expect.

Medicare Part A (inpatient care)

2021 Part A premium

  • No premium – for most beneficiaries who paid into Medicare through payroll taxes.
  • $259/month – for those who worked / paid into Medicare between 7.5 and 10 years (up from $252/month in 2020)
  • $471/month – for those with a work history of less than 7.5 years (up from $458/month in 2020)

2021 Part A deductible

  • $1,484 (up from $1,408 in 2020)
  • Covers up to 60 days in the hospital
  • Deductible is per benefit period, NOT per year. Once a beneficiary has been out of the hospital for at least 60 days, a new benefit period would start if and when they needed to be hospitalized again.
  • Supplemental coverage, including Medigap plans, will pay some or all of the Part A deductible on your behalf.

2021 Part A coinsurance:

  • $371 per inpatient day (days 61-90 in the benefit period for which the deductible applied; up from $352 per day in 2020)
  • $742 per inpatient day for day 91 and beyond during the benefit period. These are your lifetime reserve days, and you only get 60 of them over the course of your lifetime. They only start to be used up once you’ve spent 90 days in the hospital during a single benefit period. But if you do use up all your lifetime reserve days and don’t have supplemental coverage, you’re responsible for all hospital costs after the lifetime reserve days are used up (the lifetime reserve day coinsurance in 2020 is $704 per day.)
  • Medicare Part A covers 100 percent of the cost of skilled nursing facility care for the first 20 days, as long as you had at least a three-night inpatient hospital stay prior to the skilled nursing facility stay. After the first 20 days, your skilled nursing facility coinsurance in 2021 will be $185.50 per day for days 21-100 (after that, Medicare no longer covers skilled nursing facility charges, so you’ll pay the full cost). The skilled nursing facility coinsurance is $176 per day in 2020.
  • Supplemental coverage, including Medigap plans, is designed to pay the Part A coinsurance on your behalf. And all of the standardized Medigap plans will also pay for up to 365 additional days in the hospital after Medicare benefits are exhausted. Most Medigap plans also cover at least a portion of skilled nursing facility coinsurance costs.

Learn more about Medicare Part A.

Medicare Part B (outpatient care)

2021 Part B premiums:

  • The standard Part B premium for 2021 is $148.50 per month. The increase in the Part B premiums was limited by the short-term government spending bill that was signed into law on October 1, 2020. The Part B premium for most enrollees is $144.60/month in 2020, and the spending bill capped the increase for 2021 at a quarter of what it would otherwise have been. Earlier in 2020, the Medicare Trustees Report had projected a Part B premiums of $153.30 per month for most enrollees in 2021. The actual price that people pay can also also be limited by the Social Security cost of living adjustment (COLA) that beneficiaries receive, but the 1.3 percent COLA for 2021 should be adequate to allow the full standard Part B premium to be deducted from most beneficiaries’ Social Security checks.
  • High-income enrollees pay a higher Part B premium. The high-income threshold increased in 2020 to $87,000 for a single individual and $174,000 for a couple, and will be indexed annually. For 2021, the high-income threshold begins at $88,000 for an individual and $176,000 for a couple. And the Part B premium for high-income beneficiaries will range from $207.90/month to $504.90/month.
  • Part B premiums are also higher (due to a penalty) for some beneficiaries who delayed their enrollment.

2021 Part B deductible:

  • Enrollees who receive Part B-covered treatment during the year must pay the Part B deductible, which is $203 in 2020 (up from $198 in 2020).
  • Medigap plans C and F will pay the Part B deductible for you, but they’re no longer available for newly-eligible Medicare enrollees. (Plan G is still available for newly-eligible enrollees; it’s the same as Plan F except enrollees cover the Part B deductible themselves.)

Part B coinsurance:

Learn more about Medicare Part B.


Medigap premiums:

Medigap out-of-pocket costs

  • The out-of-pocket costs you’ll pay after your Medigap plan pays its share will depend on the plan design you select.

Medicare Part C (Medicare Advantage)

2021 Medicare Advantage premiums:

  • Part B premium ($148.50/month for most enrollees) + Medicare Advantage premium.
  • The average premium for Medicare Advantage plans with integrated Part D coverage is about $36/month in 2020. Across all Medicare Advantage plans, including those that do not include Part D coverage, the average premium in 2020 is about $23/month, and is expected to decrease to $21/month in 2021.

2021 Medicare Advantage maximum out-of-pocket:

  • $7,550 in 2021 (does not include prescription drug costs). But that’s the upper limit; the average Medicare Advantage plan tends to have an out-of-pocket cap below the maximum that the government allows. The maximum out-of-pocket cap (again, not counting prescription drug costs) has been $6,700 for the last several years, so the increase to $7,550 for 2021 is fairly significant.

Learn more about Medicare Advantage.

Medicare Part D prescription drug coverage

2020 Part D premiums:

  • The average premium for a basic stand-alone Medicare Part D plan is expected to be about $30.50/month in 2021. Enhanced plans will have higher average monthly premiums. There will continue to be a wide range of Part D plan options available. For 2021, premiums for Part D plans start as low as about $7/month, down from a low of about $13/month in 2020. On the higher end, plans can have premiums of up to $100/month or more, so there is a great deal of variation — in price and benefits — across the available plans.
  • High-income enrollees pay a higher Part D premium. The threshold for high-income began to be indexed as of 2020, increasing to $87,000 for a single person and $174,000 for a couple. It will increase to $88,000 and $176,000 in 2021.

Part D deductible:

  • Maximum of $445 in 2021, up from $435 in 2020. (Some plans have no deductible at all).

Part D out-of-pocket costs after deductible:

  • Not to exceed 25 percent of the cost of brand-name and generic costs.
  • There is no longer a donut hole in terms of the maximum amount that enrollees can be charged when they fill prescriptions. But the donut hole still exists in terms of how insurers design their coverage (ie, with different copay or coinsurance amounts before and after the donut hole threshold), how total drug costs are counted, and who covers the bulk of the cost of the drugs (the drug plan versus the manufacturer; see Figure 4 here).
  • After a beneficiary’s costs reach the catastrophic coverage threshold (this threshold is $6,550 in 2021, up from $6,350 in 2020), additional out-of-pocket costs are capped at the greater of 5 percent of the cost of the drug or a copay of $3.70 for generics and $9.20 for brand-name drugs. (Both of these amounts are a slight increase from 2020.)
  • Part D plans are required to cover a broad range of insulins for no more than $35/month in 2021.

Learn more about Medicare Part D.

Learn more about Medicare Extra Help, which makes prescription access more affordable for low-income beneficiaries.

Suggested Reading: Which Medicare Part D prescription drug plan should I choose?

Medicare IRMAA

A Medicare beneficiary’s income can also affect the premiums they pay for Medicare Part B and Medicare Part D. The income-related monthly adjustment amount (IRMAA) is a surcharge that’s added to premiums for Medicare Part D and Part B if a beneficiary has an income of more than $88,000 ($174,000 for a married couple). These income limits apply in 2021 (but are based on tax returns that were filed for 2019), and are indexed for inflation. For 2020, they were a little lower, at $87,000 and $174,000.

Learn more about IRMAA

Louise Norris is an individual health insurance broker who has been writing about health insurance and health reform since 2006. She has written dozens of opinions and educational pieces about the Affordable Care Act for Her state health exchange updates are regularly cited by media who cover health reform and by other health insurance experts.