When You Can Sign Up for Medicare and What You Need to Know
Who can sign up for Medicare and when
You become may be able to access for Medicare the month you turn 65, regardless of whether you're still working. If you were born on the first of the month, your may be able to access begins the month before. You do not have to retire or stop working to sign up — Medicare runs alongside employer coverage or any other insurance you have.
Some people under 65 can also sign up: those who have received Social Security disability benefits for 24 months, those with end-stage renal disease, and those with ALS (amyotrophic lateral sclerosis). The rules for these groups differ, and you should contact Social Security directly to learn what applies to your situation.
Your first chance to sign up is a seven-month window called your Initial Enrollment Period. It runs three months before the month you turn 65, through three months after. If you miss this window, you may face a permanent penalty on your premiums — so the timing matters.
Key Takeaways
- You can sign up for Medicare starting three months before you turn 65, and you have until three months after your birthday to do so without penalty.
- If you miss your Initial Enrollment Period, you will pay a higher premium for as long as you have Medicare, so acting within the window is important.
- You can sign up through Social Security, Medicare.gov, or by calling 1-800-MEDICARE, and the process takes about 15 minutes.
- If you are still working and have employer health insurance, you may be able to delay Part B without penalty, but you must tell Medicare this applies to you.
- Medicare has different parts — Part A covers hospital care, Part B covers doctor visits, and Part D covers prescription drugs — and you choose which ones you need.
The three ways to sign up
You can sign up through Social Security, through Medicare directly, or by phone. Social Security is often the simplest route if you are already receiving benefits — they can enroll you in Part A and Part B at the same time you handle other business. If you are not yet receiving Social Security, you can create an account on Medicare.gov and sign up online, or call 1-800-MEDICARE and speak to someone who can walk you through it.
Online signup through Medicare.gov takes about 15 minutes. You will need your Social Security number, proof of citizenship or legal residency (a birth certificate, passport, or naturalization papers), and information about any current health coverage. The site will tell you immediately which parts of Medicare you can sign up for and what your premiums will be.
If you call Social Security or Medicare, have the same documents ready. The person on the phone can answer questions about your specific situation — for instance, whether your employer coverage means you should delay Part B, or whether you may have access to for help paying premiums. This conversation often saves time later because they can flag issues before they become problems.
What happens if you miss your enrollment window
If you do not sign up during your Initial Enrollment Period, you enter a General Enrollment Period that runs January 1 through March 31 each year. You can sign up then, but your coverage will not start until July 1 of that year — a delay of several months.
More importantly, you will pay a permanent penalty. For Part B, the penalty is 10 percent of the standard premium for each full 12 months you were may be able to access but not enrolled. If you were may be able to access for three years and did not sign up, you pay 30 percent more than someone who enrolled on time — and you pay this extra amount for the rest of your life. Part D (prescription drug coverage) has a similar penalty structure.
There are exceptions. If you had employer coverage or were covered under a spouse's employer plan when you turned 65, you may not owe a penalty. This is called having creditable coverage. You must tell Medicare about this coverage when you sign up, and you should keep records showing the dates you had it. Without proof, Medicare will assume you owe the penalty.
Deciding which parts of Medicare to choose
Part A covers hospital stays, skilled nursing care after a hospital stay, hospice, and some home health services. Most people do not pay a premium for Part A if they or their spouse paid Medicare taxes for at least 10 years. You should sign up for Part A during your Initial Enrollment Period even if you do not sign up for anything else, because there is no penalty for late enrollment.
Part B covers doctor visits, outpatient care, lab tests, and medical equipment. It has a monthly premium (the standard amount in 2024 is $164.90, but it varies by income). You pay this premium whether you use Medicare or not. Part B is where the late-enrollment penalty applies, so if you do not need it right away, you must tell Medicare you are delaying it — do not simply skip it and plan to sign up later.
Part D is prescription drug coverage through a private insurance company that contracts with Medicare. You choose a plan during your Initial Enrollment Period, and plans vary widely in which drugs they cover and what you pay. If you do not sign up when you are first may be able to access and you go without coverage, you will owe a penalty when you eventually enroll. You can switch plans every year during the annual enrollment period (October 15 through December 7).
Part C (Medicare Advantage) is an alternative to Part A and Part B. It is offered by private insurance companies and usually includes Part D. If you choose Part C, you do not use Original Medicare; instead, you use the insurance company's network. Part C plans often have lower premiums than Part B alone, but they have networks and may require referrals. You can switch between Part C and Original Medicare once per year during the annual enrollment period.
What to do if you are still working
If you are still working and your employer has 20 or more employees, your employer's health insurance is the primary payer — it pays first, and Medicare pays second. You do not have to sign up for Part B right away. You can delay Part B without penalty as long as you have this employer coverage.
However, you must still sign up for Part A during your Initial Enrollment Period, even though you will not use it yet. And when you do sign up for Part B later, you must tell Medicare that you had creditable employer coverage. Without this documentation, you will owe a late-enrollment penalty.
If your employer has fewer than 20 employees, Medicare is the primary payer. You should sign up for Part B during your Initial Enrollment Period, because delaying it will trigger a penalty.
Documents you will need
Before you sign up, gather these documents: your Social Security number, proof of citizenship or legal residency (birth certificate, U.S. passport, naturalization certificate, or permanent resident card), and information about any current health coverage (employer insurance, COBRA, Medicaid, or Veterans benefits). If you are delaying Part B because of employer coverage, have the name of your employer and the dates you were covered.
You do not need to submit these documents when you sign up online — Medicare will verify them with the Social Security Administration. If you sign up by phone or in person, have them available so you can answer questions quickly. Keep copies for your records.
Frequently Asked Questions
What if I turn 65 but am not ready to retire?
You can sign up for Medicare and keep working. If your employer has 20 or more employees, your employer insurance stays primary and Medicare is secondary. You must still enroll in Part A during your Initial Enrollment Period, but you can delay Part B without penalty as long as you have employer coverage and tell Medicare about it.
Can I change my mind after I sign up?
Yes, during the annual enrollment period (October 15 through December 7) you can switch between Original Medicare and Medicare Advantage, or change your Part D plan. If you sign up and then realize you made a mistake, you have a limited time to change your election — contact Medicare at 1-800-MEDICARE to ask about your options.
What if I am not a U.S. citizen?
You can sign up for Medicare if you are a lawful permanent resident (green card holder) and have been in the United States for at least five years. You will need your permanent resident card and proof of your five-year residency. Other visa statuses may not may have access to — contact Social Security to learn what applies to you.
Do I have to sign up for all parts of Medicare at once?
You must sign up for Part A during your Initial Enrollment Period, but you can delay Part B and Part D if you have other coverage. You cannot delay Part A without penalty. If you delay Part B or Part D, you must tell Medicare this is intentional so they do not count it as a missed enrollment.
What happens to my current insurance when I sign up for Medicare?
If you have employer insurance, it continues to work alongside Medicare. If you have individual insurance through the marketplace, you should cancel it when Medicare starts, because you cannot use both. Contact your current insurance company to end your coverage on the date Medicare begins.