Medicare and Social Security: How They Work Together

Medicare and Social Security are two separate federal programs, but they are deeply connected. Social Security handles Medicare enrollment, collects your premiums, and determines whether you owe extra surcharges. Understanding how these two programs interact helps you make better decisions about when to claim benefits and how to manage your costs.

This guide explains the key connections between Medicare and Social Security, from automatic enrollment to premium deductions, IRMAA surcharges, and the special rules for people on disability.

Automatic Enrollment at 65

If you are already receiving Social Security retirement benefits when you turn 65, you are automatically enrolled in Medicare Parts A and B. You do not need to fill out an application or take any action. Social Security handles everything.

Your Medicare card will arrive in the mail about three months before your 65th birthday. The card shows your Medicare number and confirms that you are enrolled in both Part A (hospital insurance) and Part B (medical insurance). Coverage begins the first day of the month you turn 65.

This automatic enrollment applies to anyone receiving Social Security retirement, survivors, or spousal benefits at the time they turn 65. It also applies to people receiving Railroad Retirement Board benefits.

If you do not want Part B, you must take action to decline it. The decline form is included with your Medicare card mailing. If you do nothing, your Part B premium will be deducted from your Social Security check starting the month your Medicare coverage begins.

What If You Are Not Receiving Social Security at 65

Many people reach 65 without yet claiming Social Security retirement benefits. Some are still working. Others are delaying Social Security to increase their monthly benefit. If you are not receiving Social Security, you are not automatically enrolled in Medicare. You must apply on your own.

You can apply for Medicare at SSA.gov, by calling Social Security at 1-800-772-1213, or by visiting your local Social Security office. The application is separate from claiming Social Security retirement benefits. You can sign up for Medicare without starting your Social Security checks.

If you are not receiving Social Security, Medicare will bill you directly for your Part B premium. The bill typically arrives quarterly. You can also set up automatic payments through Medicare Easy Pay. Once you eventually start Social Security, your premiums will switch to being deducted from your monthly check.

This is a common situation, but it requires careful attention. If you forget to sign up for Medicare during your Initial Enrollment Period because you assumed it would happen automatically, you could face a gap in coverage and a permanent late enrollment penalty.

How Part B Premiums Are Deducted from Social Security

For most Medicare beneficiaries, the Part B premium is automatically deducted from their Social Security check each month. This is the default method of payment and requires no action on your part.

In 2025, the standard Part B premium is $185.00 per month. This amount is deducted before your Social Security payment is deposited. When you look at your Social Security statement, you will see the Part B deduction listed as a separate line item.

If you have additional charges, those are also deducted from your check. This includes:

• Part D premium: If you have a standalone Part D prescription drug plan, the premium may be deducted from your Social Security check.
• IRMAA surcharge: If your income is above certain thresholds, the Income-Related Monthly Adjustment Amount is added to your Part B and Part D premiums and deducted from your check.
• Late enrollment penalties: If you owe a Part B or Part D late enrollment penalty, this is included in your monthly deduction as well.

In some cases, Medicare deductions can take a significant portion of your Social Security check. This is where the hold harmless provision becomes important.

The Hold Harmless Provision

The hold harmless provision is a federal law that protects most Social Security recipients from losing money when Part B premiums increase. It ensures that a Part B premium increase cannot cause your net Social Security payment to go down compared to the previous year.

Here is how it works. Each year, Social Security adjusts benefits based on the cost-of-living adjustment (COLA). If the COLA increase is smaller than the Part B premium increase, your Part B premium is capped so that it does not reduce your net Social Security payment. The difference is absorbed by the Medicare program.

For example, imagine your Social Security check increases by $20 due to the COLA, but the Part B premium increases by $30. Under hold harmless, your Part B premium increase would be limited to $20, so your net payment stays the same. You would pay less than the full standard premium.

Not everyone is protected by hold harmless. It does not apply to:

• People who pay IRMAA surcharges (higher-income beneficiaries)
• People newly enrolled in Part B during the year
• People who have Medicare premiums billed directly rather than deducted from Social Security
• Dual-eligible beneficiaries whose premiums are paid by Medicaid

For most beneficiaries, hold harmless provides meaningful protection. In years when COLA is low but healthcare costs are rising, it prevents your Social Security income from shrinking.

IRMAA: Higher Premiums for Higher Incomes

IRMAA stands for Income-Related Monthly Adjustment Amount. It is a surcharge that higher-income Medicare beneficiaries pay on top of the standard Part B and Part D premiums. Social Security determines your IRMAA based on your modified adjusted gross income (MAGI) from your federal tax return two years prior.

For 2025, IRMAA applies if your individual MAGI exceeds $106,000 or if your joint MAGI exceeds $212,000. The surcharge increases at several income tiers. At the highest tier, the Part B premium can be more than three times the standard amount.

IRMAA applies to both Part B and Part D premiums. Even if you have a Part D plan with a low premium, the IRMAA surcharge is added separately. The surcharge is deducted from your Social Security check along with your standard premiums.

Because IRMAA uses your income from two years prior, a high-income year like a large Roth conversion, the sale of property, or an inheritance can trigger higher premiums two years later. Many people are surprised when they receive an IRMAA notice because the income event happened years earlier.

You can appeal your IRMAA determination if you have experienced a life-changing event that reduced your income. Qualifying events include retirement, divorce, death of a spouse, reduction in work hours, and loss of pension income. To file an appeal, contact Social Security and submit Form SSA-44.

Delaying Social Security but Enrolling in Medicare

A growing number of people choose to delay claiming Social Security retirement benefits beyond age 65. For each year you delay past your full retirement age (up to age 70), your monthly benefit increases by about 8%. This can result in significantly higher lifetime income.

The important thing to know is that Medicare and Social Security have completely separate enrollment timelines. You do not need to claim Social Security to enroll in Medicare. You can sign up for Medicare at 65 and delay Social Security until 70 without any problem.

However, since you will not have a Social Security check, your Part B premiums will not be deducted automatically. Instead, Medicare will send you a bill. Most people receive a quarterly bill in the mail. You can also sign up for Medicare Easy Pay to have premiums deducted directly from your bank account.

Another consideration: if you delay Social Security, you will not be protected by the hold harmless provision until you start receiving benefits. This means you will pay the full standard Part B premium each year, even if it increases substantially. Once you start Social Security, hold harmless protections kick in.

It is also critical to not miss your Medicare enrollment window. If you delay Social Security and assume Medicare will happen automatically, you may miss your Initial Enrollment Period and face permanent late enrollment penalties. Mark your calendar and apply for Medicare three months before your 65th birthday.

Social Security Disability and Medicare

If you receive Social Security Disability Insurance (SSDI), you are automatically enrolled in Medicare after a 24-month waiting period. The clock starts with the first month you are entitled to SSDI benefits, which is typically the sixth month after your disability onset due to SSDI's own 5-month waiting period.

After 24 months of SSDI eligibility, Social Security automatically enrolls you in Medicare Parts A and B. Your Medicare card arrives about three months before your coverage start date. Just like with retirement-based enrollment, you can decline Part B if you have other qualifying coverage.

The total wait from disability onset to Medicare coverage can be as long as 29 months: 5 months for the SSDI waiting period plus 24 months for the Medicare waiting period. During this gap, you may need to rely on employer coverage, COBRA, a marketplace plan, or Medicaid if you qualify.

There is one important exception: ALS (Lou Gehrig's disease). If your SSDI is based on an ALS diagnosis, the 24-month waiting period is waived. Medicare begins the same month as your SSDI entitlement. Congress created this exception because of the aggressive nature of the disease.

Note that SSDI is different from Supplemental Security Income (SSI). SSI is a needs-based program and does not automatically lead to Medicare. SSI recipients typically receive Medicaid instead. However, some people qualify for both SSDI and SSI at the same time, making them eligible for both Medicare and Medicaid.

SSA's Role in Medicare Enrollment

While Medicare is run by the Centers for Medicare and Medicaid Services (CMS), the Social Security Administration plays a central role in many parts of the program. Understanding what SSA does helps you know where to go when you have questions or problems.

Here is what SSA handles for Medicare:

• Enrollment: SSA processes all Medicare Part A and Part B enrollment applications, whether online, by phone, or in person.
• Eligibility determination: SSA verifies your work history, age, citizenship, and disability status to confirm you qualify for Medicare.
• Premium calculation: SSA determines your Part A premium based on your work credits and your Part B premium based on your income level.
• IRMAA determination: SSA reviews your tax return from two years prior and notifies you if you owe the income-related surcharge.
• Premium collection: SSA deducts Medicare premiums from your Social Security check or arranges direct billing if you are not receiving Social Security.
• Appeals: If you disagree with your IRMAA determination or believe there was an error in your enrollment, you appeal through SSA.

For questions about Medicare coverage, benefits, or claims, you contact Medicare directly at 1-800-633-4227. For questions about enrollment, premiums, or IRMAA, you contact Social Security at 1-800-772-1213.

Key Differences Between Medicare and Social Security

Although Medicare and Social Security are closely linked, they are separate programs with different rules. Here are the key differences to keep in mind.

• Different enrollment ages: Medicare eligibility begins at 65. Social Security retirement benefits can start as early as 62 or as late as 70. You do not have to claim both at the same time.
• Different funding: Social Security is funded through FICA payroll taxes, with a separate portion going to the Medicare Hospital Insurance Trust Fund. Part B and Part D are funded through beneficiary premiums and general tax revenues.
• Delaying benefits differs: Delaying Social Security increases your monthly benefit. Delaying Medicare beyond 65, without qualifying employer coverage, results in permanent late enrollment penalties. There is generally no benefit to delaying Medicare.
• Different administering agencies: Social Security is run by SSA. Medicare is run by CMS, a division of the Department of Health and Human Services. SSA handles enrollment and premium collection, while CMS handles coverage decisions, claims, and benefits.

Planning Tips: Medicare and Social Security Together

Making smart decisions about Medicare and Social Security requires thinking about both programs together. Here are some practical tips.

• Enroll in Medicare at 65 even if you delay Social Security: Unless you have qualifying employer coverage, sign up for Medicare during your IEP. Do not wait for Social Security to trigger it.
• Understand IRMAA look-back: Plan large income events like Roth conversions or asset sales carefully. IRMAA uses your income from two years prior, so a high-income year in 2024 affects your premiums in 2026.
• Budget for premiums when delaying Social Security: If you delay Social Security, you will pay Medicare premiums out of pocket. Factor the quarterly bills into your budget until Social Security checks begin.
• Know when to appeal IRMAA: If a life-changing event like retirement, divorce, or death of a spouse reduced your income, file Form SSA-44 to request a new IRMAA determination based on your current income instead of income from two years ago.

The Bottom Line

Medicare and Social Security are separate programs, but they work together in ways that directly affect your coverage and your wallet. Social Security handles your Medicare enrollment, collects your premiums, determines your IRMAA surcharges, and protects you through the hold harmless provision.

If you are receiving Social Security at 65, enrollment is automatic. If you are not, you must apply on your own. Delaying Social Security is a smart strategy for many people, but it does not delay your Medicare enrollment window. Missing your IEP because you assumed Medicare would be automatic is one of the most common and costly mistakes people make.

For people on SSDI, Medicare comes automatically after a 24-month waiting period, with the exception of ALS which has no waiting period. During the gap, you may need alternative coverage to bridge the wait.

Whether you are approaching 65, already on Medicare, or receiving disability benefits, understanding the Medicare-Social Security connection helps you avoid penalties, manage your premiums, and get the most from both programs. Contact Social Security at 1-800-772-1213 or visit SSA.gov for help with enrollment and premium questions.