Medicare is one of those things you ignore until you suddenly can't. You're cruising along, maybe thinking about retirement or just hitting that magic 65th birthday, and then—bam. You’re staring at a government website that looks like it was designed in 2004, trying to figure out the difference between "Part A" and "Plan G." It's confusing. Honestly, it’s more than confusing; it’s a bureaucratic maze that carries actual financial penalties if you trip up.
If you're wondering how to apply for Medicare, you've probably already heard the horror stories about lifelong late enrollment penalties. They're real. But the process doesn't have to be a nightmare if you know which doors to walk through and which ones to ignore.
The 65-Year-Old Starting Line
Most people get their ticket to the game during the Initial Enrollment Period (IEP). This is a seven-month window. It starts three months before the month you turn 65, includes your birth month, and ends three months after. If you miss this, you're looking at the General Enrollment Period, which runs from January 1 to March 31 each year, but that’s where the penalties start creeping in.
Don't wait. Seriously.
If you’re already collecting Social Security benefits, you’re in luck. You don't actually have to do anything. The Social Security Administration (SSA) will automatically enroll you in Medicare Parts A and B, and your red, white, and blue card will just show up in your mailbox about three months before you turn 65. It’s the one time the government makes things easy.
But what if you're still working? Or what if you delayed Social Security to get a bigger check later? Then the ball is in your court. You have to actively go to the Social Security website and hit the "Apply for Medicare" button. It takes maybe ten or fifteen minutes if you have your info ready.
How to Apply for Medicare When You’re Still Working
This is where things get sticky. If you have "creditable" coverage through an employer with 20 or more employees, you might not need Part B yet. Part A is usually free because you paid into it through your taxes for decades. Most people sign up for Part A at 65 regardless of their work status because it acts as secondary insurance for hospital stays. It costs nothing, so why not?
Part B is different. It has a monthly premium. In 2026, those premiums aren't getting any cheaper.
If your company has fewer than 20 people, Medicare usually becomes your primary insurance the second you turn 65. If you don't sign up, your private insurance might refuse to pay your bills, claiming Medicare should have covered it. You’ll be stuck in the middle of a very expensive finger-pointing match.
To sign up while working, or when you finally decide to retire after 65, you use a Special Enrollment Period (SEP). You’ll need two specific forms: the CMS-40B (the application) and the CMS-L564 (which your employer fills out to prove you’ve had insurance). You can't always do this part online. Sometimes you have to mail these forms to your local Social Security office or drop them off in person. It feels old school because it is.
The "Parts" vs. The "Plans"
People use these words interchangeably, but they aren't the same. This is the biggest trap.
- Part A: Hospital insurance.
- Part B: Medical insurance (doctors, labs, etc.).
- Part D: Drugs.
- Part C: Medicare Advantage (the "all-in-one" private alternative).
Then you have Medigap, which are also called "Plans" (like Plan G or Plan N). These are supplements to Original Medicare. You cannot have Medicare Advantage and a Medigap plan at the same time. It’s an "either-or" situation.
Most experts, like those at the Medicare Rights Center, suggest looking closely at the network restrictions. Medicare Advantage often looks cheaper because the premiums are low (sometimes $0), but you’re restricted to a specific network of doctors. If you want to see a specialist in another state, you might be out of luck. Original Medicare plus a Medigap plan lets you see any doctor in the country that accepts Medicare. That’s about 90% of them.
The Paperwork Reality Check
When you actually sit down to figure out how to apply for Medicare, have your documents ready. You'll need your Social Security number, your place of birth, and potentially your tax returns from two years ago. Why two years ago? Because of IRMAA.
The Income Related Monthly Adjustment Amount (IRMAA) is a surcharge for higher earners. If you made over a certain threshold (usually starting around $100k for individuals), the government decides you can afford to pay more for Part B and Part D. They look at your tax returns from two years prior to determine this. If your income has dropped since then—maybe because you retired—you can appeal this using Form SSA-44.
Avoid the "Late" Tax
The Part B penalty is 10% for each full 12-month period you could have had Part B but didn't. This isn't a one-time fine. It stays with you for the rest of your life. The Part D (drug) penalty is even more granular, calculated at 1% of the "national base beneficiary premium" for every month you went without creditable coverage.
Basically, if you go three years without coverage, your Part B premium will always be 30% higher than everyone else's. Forever.
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Navigating the Online Portal
The most efficient way to get this done is through the ssa.gov website. You'll need to create a "my Social Security" account. They’ve added multi-factor authentication now, so have your phone handy for those text codes.
- Log in to your account.
- Find the "Medicare Enrollment" section.
- Answer the questions about your current health coverage.
- Submit.
You don’t get a confirmation immediately. It takes a few weeks for the bureaucracy to churn. You can check your status on the same portal. Once approved, you can log into medicare.gov to shop for drug plans or Advantage plans.
The Medigap Open Enrollment Window
This is a one-time-only deal. It starts the month your Part B becomes effective and lasts for six months. During this window, private insurance companies must sell you a Medigap policy regardless of your health. No medical underwriting. No questions about your heart condition or that hip replacement you need.
If you wait until you're 67 to try and buy a Medigap plan, the company can look at your medical records and say "no thanks" or charge you triple. This is why the timing of how to apply for Medicare is so much more important than the actual application itself.
Specific Actionable Steps to Take Right Now
If you are within 6 months of turning 65, stop guessing and start doing.
Check your "creditable coverage" status if you're still working. Ask your HR department specifically: "Is my health insurance considered primary or secondary to Medicare?" Get it in writing. This protects you later if Social Security tries to claim you have a late enrollment penalty.
Create your "my Social Security" account today. Don't wait until the month you turn 65 because sometimes the identity verification process takes a week or two if they can't verify your records electronically.
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Gather your tax info from two years ago to see if you'll hit the IRMAA surcharges. If you've had a "life-changing event" like retirement, marriage, or divorce that dropped your income, download Form SSA-44 so you're ready to contest the higher premium.
Compare the total cost of ownership between Medicare Advantage and Original Medicare with a Medigap supplement. Don't just look at the monthly premium. Look at the "Maximum Out of Pocket" (MOOP) limit. For some Advantage plans, that can be as high as $8,000 or more annually. A Medigap Plan G might cost $150 a month but leaves you with almost zero out-of-pocket costs for the rest of the year.
Decide on a Part D drug plan even if you don't take any prescriptions right now. Pick the cheapest one available just to "park" your enrollment and avoid the lifetime late penalty. You can always switch to a more robust plan during the Open Enrollment Period (October 15 – December 7) if your health needs change later.