Turning 65: when to sign up for Medicare

Most people first sign up for Medicare around their 65th birthday. Getting the timing right avoids gaps in coverage and penalties that can last for life.

Your Initial Enrollment Period is 7 months

It starts 3 months before the month you turn 65, includes your birthday month, and ends 3 months after. If you already get Social Security benefits, you're usually enrolled in Part A and Part B automatically and your card arrives in the mail.

Still working? You may be able to wait

If you (or your spouse) are still working and covered by that employer's group health plan, you can often delay Part B without a penalty. When the job or the coverage ends, you get a Special Enrollment Period of 8 months to sign up. Check with the employer's benefits office first, because the rules depend on the size of the employer. More: your Special Enrollment Period when job coverage ends.

Late penalties

If you don't sign up for Part B when you're first eligible and don't have qualifying coverage, your Part B premium can go up 10% for each full 12 months you could have had it, for as long as you have Part B. Part D has its own late penalty if you go 63 days or more without creditable drug coverage.

The Medigap window

Your Medigap Open Enrollment Period lasts 6 months, starting the first month you're 65 or older and enrolled in Part B. During it, insurers can't refuse to sell you a Medigap policy or charge you more because of your health. After it, in most states, they can.

More on every window: Medicare enrollment periods, explained.