How do Social Security and Medicare work together?

Social Security and Medicare are distinct programs serving older and disabled Americans, but they have an important commonality: Social Security handles enrollment for Medicare Part A (hospital insurance) and Part B (medical insurance).

In this role, the Social Security Administration (SSA) works with the Centers for Medicare & Medicaid Services (CMS) to inform older Americans about their Medicare sign-up options, process their applications and collect premiums.

Managing Medicare enrollment

For most people, Medicare eligibility starts at age 65. If you're receiving Social Security retirement benefits at that time, SSA will send you a Medicare enrollment package at the start of your initial enrollment period, which begins three months before the month you turn 65. For example, if your 65th birthday is July 15, 2025, this period begins April 1.

On your 65th birthday, you'll automatically be enrolled in parts A and B. You have the right to opt out of Part B, but you might incur a penalty, in the form of permanently higher premiums, if you sign up for it later.

If you have not yet filed for Social Security benefits, you will need to apply for Medicare yourself. You can do so any time during the initial enrollment period, which lasts seven months (so, for that July 15 birthday, the sign-up window runs from April 1 through Oct. 31). If you do not enroll during that period, you could face those late fees if you do so later.

You'll find comprehensive enrollment information in SSA's “Medicare” publication and links to application forms on the Social Security website.

Paying Medicare premiums

If you are drawing Social Security benefits, your Medicare Part B premiums are deducted from your monthly payments. If you're not getting benefits, you'll receive bills from CMS. (Almost all Medicare beneficiaries pay no premiums for Part A because they worked, and paid Medicare taxes, long enough to qualify for the program.)

The standard Part B premium paid by most Medicare enrollees is $185 a month in 2025. The rate rises with the beneficiary's income, going up in steps for individuals with incomes greater than $106,000 in 2025 and married couples who file taxes jointly and have a combined income of more than $212,000 in 2025. 

Social Security determines whether you will pay a higher premium based on income information it receives from the IRS.

Keep in mind

• People with disabilities may qualify for Medicare before age 65. If you are receiving Social Security Disability Insurance (SSDI), Social Security will enroll you automatically in Parts A and B after you have been drawing benefits for two years.
• If you have Medicare Part D (prescription drug plan) or a Medicare Advantage plan, also known as Medicare Part C, you can elect to have the premiums deducted from your monthly Social Security payment.