Straight answer
When do I need to sign up for Medicare?
Generally when you turn 65. Your Initial Enrollment Period lasts 7 months: it starts 3 months before the month you turn 65 and ends 3 months after it. If your birthday is on the 1st of a month, the window shifts a month earlier: it runs from 4 months before the month you turn 65 to 2 months after. If you're already getting Social Security at least 4 months before you turn 65, you're enrolled automatically. Otherwise, you need to sign up. Miss your window without other qualifying coverage and you can owe a Part B late penalty, usually for life.
How big is the Part B late penalty?
An extra 10% on your Part B premium for each full 12-month period you could have signed up but didn't. For most people it lasts for as long as they have Part B.
I still have health insurance through work. Do I have to sign up at 65?
You may be able to wait. If you or your spouse are still working and have group health coverage through that job, you can get a Special Enrollment Period. It runs until 8 months after the job or the coverage ends, whichever happens first, and you generally won't owe a Part B penalty if you qualify.
I have a Health Savings Account. Anything to watch?
Yes. You and your employer should stop contributing to your HSA 6 months before you retire or apply for benefits, to avoid a tax penalty.
Does COBRA count as coverage through work?
No. COBRA isn't considered group health plan coverage for this purpose, so it doesn't get you a Special Enrollment Period.
If I'm enrolled automatically, do I get everything?
You get Part A (hospital insurance). Whether you also have Part B (medical insurance) can depend on what you chose when you applied for Social Security, so check your Medicare card or welcome package.
- Medicare.gov — When does Medicare coverage start?
- Medicare.gov — How do I sign up for Medicare?
- Medicare.gov — Avoid late enrollment penalties
- Medicare.gov — Working past 65
- Railroad Retirement Board — Medicare enrollment rules simplified
- Social Security Administration — Delayed retirement credits
Money Mechanics explains how things work in plain language. It is not personalized financial advice.
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