How do I apply for Medicare?

You apply through Social Security, online at ssa.gov, by phone at 1-800-772-1213, or in person at a local office. If you already receive Social Security benefits, you are enrolled in Parts A and B automatically.

Can I apply for Medicare online?

Yes. The online application at ssa.gov takes about 10 minutes, you can save it and return to it, and there is nothing to sign. It is the fastest way to enroll in Parts A and B.

How do I sign up for Medicare if I am still working?

If you are covered by a group health plan through current employment, you can usually delay Part B and enroll later using a Special Enrollment Period, which runs 8 months from when the job or the coverage ends. Your employer completes form CMS-L564 to confirm the coverage dates. COBRA and retiree coverage do not count as current employment.

Can I enroll in Medicare if I have end-stage renal disease?

Yes, but it is not automatic the way it is for people already collecting benefits. You have to apply through Social Security yourself.

How long does Medicare enrollment take?

Social Security usually processes the application within a few weeks and mails your Medicare card. Your coverage start date depends on when in your Initial Enrollment Period you applied.

Do I apply for Medicare through Social Security or Medicare?

You enroll in Parts A and B through Social Security. Medicare.gov is where you later compare and join Part D drug plans and Medicare Advantage plans, and manage your coverage.

Medicare 101

How to Enroll in Medicare, Step by Step

Enrolling in Medicare Parts A and B is handled by Social Security, not Medicare. This guide covers whether you are signed up automatically, which window applies to you, how to apply, and the choice people rush at the end.

Forrest Klein · Licensed Insurance Agent

Last reviewed November 3, 2026

First, check whether you are enrolled automatically

Find Out If You Are Enrolled Automatically before you do anything else, because some people never have to apply at all. Signing up for Medicare is only necessary if Social Security has not already done it for you, which it does in a few specific situations when you turn 65. Your red, white and blue card then arrives in the mail about three months before coverage starts. If you do not want Part B yet because you have job-based coverage, the card comes with instructions for turning it down.

Already collecting benefits: You receive Social Security or Railroad Retirement benefits at least 4 months before you turn 65.
On disability 24 months: You are under 65 and have received Social Security disability benefits for 24 months.
ALS: Coverage starts the same month your disability benefits start, with no 24-month wait.
End-stage renal disease is different: ESRD is never automatic. You have to apply through Social Security yourself.

Know which enrollment window you are in

Know Your Medicare Enrollment Windows before anything else, because if you are not enrolled automatically, timing is the thing that costs money. Four windows exist and they do completely different jobs, which is where most of the confusion comes from, and missing the right one brings a late enrollment penalty.

Initial Enrollment Period: A 7-month window: 3 months before your birthday month, the month itself, and 3 months after. Sign up before your birthday month and coverage starts on the 1st of it.
Special Enrollment Period: For people still covered by a current employer's group plan. It runs 8 months from when the job or the coverage ends, whichever comes first.
General Enrollment Period: January 1 to March 31, for anyone who missed their window and has no SEP. Coverage starts the following month and a late penalty usually applies.
Open Enrollment is not a sign-up window: October 15 to December 7 is for CHANGING coverage you already have. It will not get you onto Part A or Part B for the first time.

Questions about your Medicare options?

Talk to a licensed insurance agent, at no cost.

1-800-940-0633

COBRA and retiree coverage do not protect you

This is the single most expensive misunderstanding on this page. Only coverage based on current employment lets you delay Part B without a penalty, which means being still working, not merely still covered. COBRA and retiree plans do not count, no matter how good they are, so waiting for COBRA to run out before signing up is how people end up with a lifetime surcharge. Other life events open their own windows, including moving or losing Medicaid. If you are weighing it, check before you drop anything.

Three ways to apply

You enroll in Parts A and B through the Social Security Administration, not through Medicare. Online is fastest: the application takes about 10 minutes, you can save it and come back, and nothing needs to be signed. A free my Social Security account at ssa.gov lets you check the status afterwards.

Online: ssa.gov, about 10 minutes, no forms to sign. The fastest route for most people.
By phone: Social Security at 1-800-772-1213, TTY 1-800-325-0778.
In person: Your local Social Security office. Call ahead and book, rather than walking in.
Railroad retirement: Contact the Railroad Retirement Board at 1-877-772-5772 instead of Social Security.

What to have in front of you

Applying online takes most people under 30 minutes when they have the details ready. If you are delaying Part B because of active employer coverage, keep records of it: you will need them for a Special Enrollment Period later, and your employer completes form CMS-L564 to confirm the dates.

Your Social Security number: Plus your date and place of birth.
Current coverage details: Any health plan you have now, and the dates it started.
Your spouse's information: If you are married, including their work and coverage history.
Employer coverage dates: Required if you are using a Special Enrollment Period.

What Parts A and B cost

Part A is hospital insurance, and most people get it at no premium because they or a spouse paid Medicare taxes for about 10 years. Since it usually costs nothing, most people take it at 65 even while working. Part B has a monthly premium, $202.90 as the standard amount in 2026, and people with higher incomes pay more through IRMAA. Skip Part B when you are first eligible without qualifying job coverage and the penalty is 10% for every full 12-month period you could have had it, charged for as long as you stay enrolled.

Health savings accounts: Stop HSA contributions 6 months before Part A starts. Part A can backdate up to 6 months, and contributions made during a month you were covered are penalized.
The Part B penalty is permanent: It is not a one-time fee. It is added to your premium for life.

Then choose how you actually get your coverage

This is the step people rush, and it shapes your costs and your choice of doctors for years. Once you have Parts A and B you choose your coverage from one of two routes: keep Original Medicare and add a Medigap plan for your share of the costs plus a Medicare Part D plan for drugs, or take a Medicare Advantage plan that bundles it together. There is no universally right answer: it depends on your doctors, your prescriptions, your budget and how much risk you want to carry.

Original Medicare plus extras: Keep Parts A and B, add a Medigap plan for your share of costs and a stand-alone Part D plan for drugs.
Medicare Advantage: A private plan bundling hospital, medical and usually drug coverage, often with extras. You must have Parts A and B first.
The Medigap window closes: Your 6-month Medigap open enrollment starts when you are 65 and have Part B. Inside it you cannot be turned down or charged more for your health. Afterwards, in most states, you can be.

Do not skip drug coverage

Going 63 days or more without Part D or other creditable drug coverage after your Initial Enrollment Period adds a penalty to your premium for as long as you have Part D. It is worth taking a cheap plan you barely use rather than carrying a surcharge for life. For 2027, a drug plan's deductible can be no more than $700, and once your out-of-pocket drug costs reach $2,400 you pay nothing for covered drugs for the rest of the year.

Mistakes that cost people money

Every one of these is common, and every one is avoidable with a calendar reminder.

Waiting for a letter: If you are not already collecting benefits, nobody enrolls you. Nothing arrives.
Trusting retiree coverage: Only current-employment coverage lets you delay Part B penalty-free.
Missing the 63-day drug deadline: A gap of 63 days or more can mean a penalty that lasts for life.
Dropping job coverage too early: Compare the real costs first. The employer plan is sometimes still the better deal.
Forgetting a spouse: Each person enrolls separately, even when one spouse's job covers both.

After you apply, and where to get help

Social Security processes most applications within a few weeks and mails your Medicare card. Your start date depends on when in your Initial Enrollment Period you applied: sign up in the first 3 months and coverage begins the month you turn 65. If you want a second opinion that is not a sales call, your State Health Insurance Assistance Program offers free unbiased counseling, and 1-800-MEDICARE (1-800-633-4227) is the official line. A licensed insurance agent can compare plans with you at no cost.