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What is open enrollment?

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What is it?Insurance typesAffordable Care Act enrollmentSpecial vs. open enrollmentSummary
Open enrollment is a set period of time every year when you can sign up or change your health insurance coverage. The timing may vary and depends on whether you have coverage from your employer, the Affordable Care Act (ACA), or Medicare.
Medically reviewed by Debra Sullivan, Ph.D., MSN, R.N., CNE, COI
Written by Cathy Lovering
Updated on

Health insurance companies restrict when you can change or start your health coverage to a certain period of a few weeks or months each year. This period is called open enrollment.

Usually, you can’t change your plan outside of open enrollment. That said, many exceptions do exist that might allow you to adjust your coverage.  

Definition of open enrollment

Woman on her laptop signing up for health insurance during open enrollment
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Open enrollment is when you can sign up, change, or confirm a health insurance plan for the following year. This means staying with your current health insurance, switching to a different one, or getting health insurance for the first time.

Open enrollment always happens before your coverage effective date (starting date of coverage). For a health insurance plan that starts coverage on January 1, open enrollment typically closes a few weeks earlier.

The window for open enrollment depends on whether you’re getting a plan through the Health Insurance Marketplace, your employer, Medicare, or another source. 

The open enrollment window reduces the risk to insurance companies. People who expect high health costs are usually more motivated to purchase insurance premiums, while those who don’t expect to need health services might delay the process. 

Limiting the period when you can sign up for or change a health insurance plan ensures a balance of insured people who use the coverage and those who don’t.

During open enrollment, you have access to information about the health plans offered through the insurance company, their benefits, and the initial and monthly cost to you. Then, you can sign up for whichever plan suits your needs best.

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What types of health insurance have open enrollment periods?

Some types of health insurance, such as Medicaid and the Children’s Health Insurance Program (CHIP), accept new enrollment year-round.

Other types of insurance companies have set specific enrollment periods, including:

  • plans through the Health Insurance Marketplace established by the ACA
  • plans through your employer
  • Medicare

Open enrollment for the Health Insurance Marketplace is every year from November 1 to January 15. Some states have their own marketplace and may set a different open enrollment period. A marketplace is a digital place where you can browse and compare various health benefits and companies, then shop the one for you and your family.

Companies offering health insurance coverage to employees also set open enrollment periods around the third quarter of the year, even though enrollment may happen at any time. It usually lasts 2–4 weeks. Your employer can let you know exactly how it works. 

Medicare open enrollment is usually between October 15 and December 7 and may involve checking different coverages and benefits. 

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Is open enrollment different under the Affordable Care Act?

No. ACA also has an open enrollment period from November to mid-January. Open enrollment applies to most people getting individual or family health insurance.

For your health coverage to come into effect on January 1, you’d have to sign up during open enrollment by December 15. If you sign up between December 16 and January 15, your coverage will start on February 1.

ACA determines that some states have autonomy over when and how their open enrollment period works. In Idaho, for example, the open enrollment period goes from October 15 to December 15.

Some states might refer to their Health Insurance Marketplace as a Health Insurance Exchange. Though the name may differ, the concept is the same. 

To get a new plan or change your plan on the Health Insurance Marketplace, you create an account at If your state does not use the Marketplace, you should visit the site for your state’s Health Insurance Exchange.

After creating an account and logging in, you can enter your information, then view and compare health plans. 

In addition to applying online, you have these options during open enrollment to get health insurance through the Marketplace:

  • Fill out and mail in a paper application.
  • Complete your application and compare plans over the phone with the Marketplace Call Center.
  • Work with a certified enrollment partner, such as an insurance company.
  • Get help from a local support center.

Special enrollment vs. open enrollment

Life events may mean you can sign up for or change your existing health insurance plan outside of the open enrollment period. This is sometimes referred to as special enrollment.

If you qualify for special enrollment, you must make the change within 60 days of the qualifying life event.

Life events that can qualify for special enrollment include:

  • Household changes: life events such as marriage or a new baby, or loss of coverage because of reasons like divorce or job loss
  • Changes in residence: a move to a new ZIP code or county, school, workplace, or transitional housing
  • Loss of health insurance: loss of insurance through your employer or loss of coverage because of eligibility changes under Medicare Part A or a Marketplace plan
  • Newly offered employer support: for the cost of health insurance coverage

If you are turned down for the special enrollment period exception, you may appeal within 90 days of the decision.


The open enrollment period allows you to sign up for a new health insurance plan, whether one offered by your employer, Medicare, or the ACA through the Health Insurance Marketplace. Open enrollment usually happens for a few weeks once per year.

If you experience major life events — such as marriage, a new child, or loss of coverage — you may be able to change or sign up for health insurance outside of the open enrollment period. 

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