Official Medicare Publications & Guides

Enrolling in Medicare Part A & Part B

Learn when and how to enroll in Medicare Part A and Part B. Understand automatic enrollment for Social Security recipients, Initial Enrollment Periods, Special Enrollment options for workers with employer coverage, and how to avoid costly late enrollment penalties.

Jan 31, 2018 · 5 min read

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Who Should Read This

This guide is essential reading for anyone approaching age 65 or already eligible for Medicare. It provides critical information for people who need to understand when and how to enroll in Medicare Part A and Part B, including those receiving Social Security benefits, those still working with employer coverage, and individuals with disabilities or End-Stage Renal Disease. Family members and caregivers helping loved ones navigate Medicare enrollment will also find this information valuable.

Quick Overview

This publication explains how to enroll in Medicare Part A and Part B, covering both automatic and manual enrollment processes. It details the Initial Enrollment Period, Special Enrollment Periods, and General Enrollment Period, along with important information about avoiding late enrollment penalties. The guide helps readers understand the connection between Social Security benefits and Medicare enrollment timing.

Key Takeaways

People receiving Social Security benefits at least four months before turning 65 are automatically enrolled in Medicare Parts A and B when they turn 65
The Initial Enrollment Period spans seven months, beginning three months before your 65th birthday month and ending three months after
Those not receiving Social Security benefits must actively sign up for Medicare through the Social Security Administration
Delaying Part B enrollment without qualifying for a Special Enrollment Period results in late enrollment penalties that last as long as you have coverage
Current workers with employer group health coverage may qualify for a Special Enrollment Period to delay enrollment without penalties
The General Enrollment Period runs January 1 through March 31 each year for those who missed their initial enrollment window
Part A is premium-free for most people who worked at least 10 years in Medicare-covered employment

Publication Summary

Enrolling in Medicare Part A and Part B represents an important milestone in healthcare coverage. Understanding the enrollment process helps avoid coverage gaps and financial penalties that can affect healthcare costs for years to come.

Medicare Part A, known as hospital insurance, covers inpatient hospital stays, skilled nursing facility care, hospice care, and some home health services. Most people qualify for premium-free Part A if they or their spouse paid Medicare taxes through employment for at least 10 years. Medicare Part B covers doctor visits, outpatient services, preventive care, medical equipment, and other healthcare services not covered by Part A. Part B requires a monthly premium that varies based on income level.

The enrollment process differs depending on whether someone is already receiving Social Security benefits. Those who start receiving Social Security retirement or disability benefits at least four months before turning 65 receive automatic enrollment in both Part A and Part B. The Social Security Administration mails a welcome package with the Medicare card about three months before coverage begins. People who delay Social Security benefits past age 65 must actively enroll in Medicare by contacting Social Security online, by phone, or in person at a local office.

The Initial Enrollment Period provides the first opportunity to enroll in Medicare without penalties. This seven-month window starts three months before the 65th birthday month, includes the birthday month, and extends three months afterward. The timing of enrollment during this period affects when coverage begins. Enrolling during the first three months ensures coverage starts the month of turning 65. Signing up during the birthday month or the following three months delays the coverage start date by one to three months.

Special circumstances allow some people to delay Medicare enrollment without facing penalties through Special Enrollment Periods. Workers who maintain group health coverage through an employer with 20 or more employees can postpone Part B enrollment. This applies to active employment coverage, not retiree benefits or COBRA continuation coverage. The Special Enrollment Period extends for eight months after employment ends or group coverage stops, whichever comes first. Failing to enroll during this eight-month window means waiting for the General Enrollment Period and potentially paying penalties.

The General Enrollment Period serves as a safety net for people who missed their Initial Enrollment Period and do not qualify for a Special Enrollment Period. Running from January 1 through March 31 each year, this period allows late enrollment in Part A and Part B. However, coverage does not begin until July 1, creating a potential gap in coverage. More significantly, late enrollment penalties apply and continue for as long as the person has Medicare coverage.

Late enrollment penalties increase the longer someone waits to enroll. The Part B penalty adds 10 percent to the monthly premium for each full 12-month period someone was eligible but did not enroll. This penalty is not a one-time fee but an ongoing increase that continues indefinitely. People who need to purchase Part A face similar penalties if they delay enrollment without qualifying for a Special Enrollment Period.

Certain groups face unique enrollment situations. People under 65 with disabilities automatically receive Medicare after receiving Social Security Disability Insurance benefits for 24 months. Those with Amyotrophic Lateral Sclerosis receive immediate Medicare coverage when disability benefits begin. Individuals with End-Stage Renal Disease have specific enrollment rules and timeframes that differ from standard Medicare eligibility.

Understanding the relationship between Social Security and Medicare helps with planning. While Social Security retirement benefits can begin as early as age 62, Medicare eligibility typically starts at 65. This creates a gap where someone might receive Social Security without Medicare coverage. Conversely, people who wait until after 65 to claim Social Security benefits need to actively enroll in Medicare to avoid penalties and coverage gaps.

Frequently Asked Questions

Do I need to sign up for Medicare if I am receiving Social Security benefits?
No, you will be automatically enrolled in Medicare Parts A and B if you are receiving Social Security benefits at least four months before you turn 65. You will receive your Medicare card in the mail about three months before your coverage starts.

Can I delay Medicare enrollment if I have employer coverage?
Yes, you can delay Part B enrollment without penalty if you have coverage through active employment with a group health plan from an employer with 20 or more employees. You must enroll within eight months of when your employment or coverage ends to avoid penalties.

What happens if I miss my Initial Enrollment Period?
If you miss your Initial Enrollment Period and do not qualify for a Special Enrollment Period, you must wait until the General Enrollment Period, which runs from January 1 through March 31 each year. Your coverage will not start until July 1, and you will likely face late enrollment penalties.

When does my Medicare coverage actually start?
Coverage start dates depend on when you enroll during your Initial Enrollment Period. If you enroll in the three months before your birthday month, coverage begins the month you turn 65. Enrolling during your birthday month starts coverage the following month, and enrolling in the months after your birthday delays coverage further.

How much are the late enrollment penalties?
The Part B penalty is 10 percent of the monthly premium for each full 12-month period you were eligible but did not enroll. This penalty continues for as long as you have Part B coverage. Part A penalties apply only to those who must purchase Part A and follow similar calculation methods.