Medicare General Enrollment Period (GEP): Dates, Rules, and Penalties

Updated June 4, 20267 min readReviewed against medicare.gov

The Medicare General Enrollment Period (GEP) runs January 1 through March 31 every year. It is a second chance to sign up for Medicare Part B (and premium Part A) if you missed your Initial Enrollment Period and don't qualify for a Special Enrollment Period. If you enroll during the GEP, your coverage starts the first day of the month after you sign up. Because you delayed enrollment, you will usually owe a Part B late enrollment penalty of 10% for each full 12-month period you could have had Part B but didn't, and you pay it for as long as you have Medicare.

What is the General Enrollment Period and when is it?

The General Enrollment Period (GEP) is a yearly window from January 1 through March 31 when you can sign up for Medicare Part B, and for premium Part A if you have to buy it.

The GEP exists as a safety net. If you didn't enroll when you were first eligible during your Initial Enrollment Period (the 7-month window around your 65th birthday), and you don't qualify for a Special Enrollment Period, the GEP is your chance to get into Original Medicare. There is no income or health requirement to use it.

Open every year from January 1 through March 31.
Used to enroll in Part B and, if needed, premium Part A.
For people who missed their Initial Enrollment Period and have no Special Enrollment Period.

Who should use the General Enrollment Period?

The GEP is for people who did not sign up for Part B (and/or premium Part A) when they were first eligible, and who do not qualify for a Special Enrollment Period.

Before you rely on the GEP, check whether a Special Enrollment Period (SEP) applies to you. An SEP can let you enroll outside the normal windows without a late penalty, for example if you delayed Part B because you had qualifying coverage from a current job (yours or your spouse's). If an SEP fits your situation, use it instead of the GEP to avoid the late enrollment penalty.

You missed your 7-month Initial Enrollment Period around age 65.
You do not have a Special Enrollment Period available.
You need Part B coverage and are willing to accept any applicable late penalty.

When does coverage start if I sign up during the GEP?

If you enroll during the General Enrollment Period, your Part B and premium Part A coverage starts the first day of the month after you sign up.

For example, if you sign up on February 15, your coverage begins March 1. This is a change from older rules that pushed coverage to July 1, so today's GEP enrollees get covered much faster.

How is the GEP different from other Medicare enrollment periods?

It's easy to confuse the General Enrollment Period with other Medicare windows, because some overlap on the calendar. The key difference is purpose: the GEP is for enrolling in Original Medicare (Part A and Part B) for the first time, not for switching plans.

Initial Enrollment Period (IEP): the 7-month window around your 65th birthday when you first sign up. Enrolling here avoids late penalties.
Special Enrollment Period (SEP): for those who delayed enrollment for a qualifying reason, such as employer coverage. Usually no late penalty.
General Enrollment Period (GEP): January 1 - March 31, for first-time Part A/B sign-up if you missed the IEP and have no SEP. Penalties usually apply.
Medicare Open Enrollment (October 15 - December 7): for changing Medicare Advantage or Part D drug plans, not for enrolling in Original Medicare.
Medicare Advantage Open Enrollment (January 1 - March 31): for people already in a Medicare Advantage plan to switch plans or return to Original Medicare, not for first-time Original Medicare sign-up.

Will I owe a late enrollment penalty, and how much?

Signing up during the GEP instead of when you were first eligible usually means a late enrollment penalty. The penalty is added to your monthly premium, so it raises your costs every month.

Part B late enrollment penalty: your Part B premium goes up 10% for each full 12-month period you could have had Part B but didn't sign up, and you pay this higher amount for as long as you have Medicare. The penalty is added to the standard 2026 Part B premium of $202.90 per month. For example, if you waited two full years, that's a 20% penalty, or about $40.58 extra per month on top of the base premium.

Premium Part A late enrollment penalty: if you have to buy Part A and signed up late, your premium may go up 10%, and you pay the higher premium for twice the number of years you could have had Part A but didn't sign up. Most people get Part A premium-free (40+ work quarters); those who must buy it pay $311 per month with 30-39 quarters of work or $565 per month with under 30 quarters.

Part D late enrollment penalty: a separate penalty may apply if you went 63 or more days in a row without creditable drug coverage. It equals 1% of the national base beneficiary premium ($38.99 in 2026) for each full month you went without coverage, and it's added to your Part D premium for as long as you have drug coverage.

How to sign up and add Advantage or drug coverage

You sign up for Part B (and premium Part A) through the Social Security Administration, online at SSA.gov, by phone, or at a local office. Once enrolled, your Original Medicare takes effect the first of the month after you sign up.

After your Original Medicare is in effect, you can add other coverage. To join a Medicare Advantage Plan (Part C) you must have both Part A and Part B. To join a Part D drug plan you need Part A and/or Part B. So GEP enrollees can add Medicare Advantage or a Part D plan once their Original Medicare is active.

For reference, the standard 2026 Part B costs are a $202.90 monthly premium and a $283 annual deductible, after which you generally pay 20% of the Medicare-approved amount for most covered services.

Enroll in Part A/B through Social Security (online, phone, or in person).
Coverage starts the first day of the month after you sign up.
Part C (Medicare Advantage) requires both Part A and Part B.
Part D (drug coverage) requires Part A and/or Part B.

Frequently asked questions

What are the General Enrollment Period dates?

The General Enrollment Period runs January 1 through March 31 every year. If you enroll during this window, your Part B and premium Part A coverage begins the first day of the month after you sign up.

Can I avoid the GEP penalty with a Special Enrollment Period?

Often, yes. If you delayed enrolling in Part B for a qualifying reason, such as having health coverage from a current job, you may qualify for a Special Enrollment Period that lets you sign up without the late penalty. Check whether an SEP applies before relying on the GEP.

How is the Part B late enrollment penalty calculated?

Your Part B premium increases 10% for each full 12-month period you could have had Part B but didn't enroll, and you pay it for as long as you have Medicare. The penalty is added to the standard 2026 premium of $202.90 per month.

Can I join a Medicare Advantage or Part D plan after enrolling during the GEP?

Yes. Once your Original Medicare is in effect, you can add coverage. A Medicare Advantage plan requires both Part A and Part B, and a Part D drug plan requires Part A and/or Part B.

What does Part B cost in 2026?

The standard 2026 Part B premium is $202.90 per month with a $283 annual deductible. After the deductible, you generally pay 20% of the Medicare-approved amount for covered services. A late enrollment penalty, if you owe one, is added on top of the premium.

Sources

Related guides

Enrollment & Eligibility

Working Past 65: Do You Have to Sign Up for Medicare?

Medicare Login Guide is an independent resource and is not affiliated with or endorsed by Medicare, the Centers for Medicare & Medicaid Services, or any government agency. This article is for general information only — confirm current figures and your specific options at medicare.gov or by calling 1-800-MEDICARE.