Turning 65: your Medicare deadlines

Checklist

1. About 3 months before you turn 65: if your Social Security benefits started at least 4 months before you turn 65, you'll be enrolled in Part A and Part B automatically and your Medicare card comes in the mail. If not, sign up with Social Security, online at ssa.gov, by phone or at an office.
2. Still working? Ask your employer's plan how it works with Medicare before you decide on Part B. Many people take premium-free Part A at 65 and delay Part B while they have job coverage.
3. Have a Health Savings Account? Medicare.gov suggests stopping contributions at least 6 months before you apply, because premium-free Part A can start up to 6 months back (not before 65) and you can't contribute once you have Medicare.
4. Drug coverage: join a Part D plan during the same 7 months, or a Medicare Advantage plan with drugs once you have both Part A and Part B, unless you have other coverage at least as good (creditable). Going 63 days or more in a row without creditable drug coverage after your window can mean a permanent Part D penalty. Part D 2027 costs.
5. Medigap: if you want a Medigap policy, buy it in the 6 months starting the first month you're 65 or older and have Part B. In that window, insurers can't turn you down or charge more because of your health, though a policy can make you wait for coverage of a pre-existing condition. Medicare Advantage vs Medigap.
6. Check your income for IRMAA: your premiums depend on your tax return from two years earlier. IRMAA calculator.

When coverage starts

Premium-free Part A starts the month you turn 65 if you sign up within 6 months of it. If you sign up later, it starts up to 6 months back, but not before the month you turned 65.

If you delay Part B

With health coverage from your or your spouse's current job, you can sign up for Part B any time while you're covered, or in the 8 months after the job or the coverage ends, whichever comes first. COBRA and retiree coverage don't count, and having COBRA doesn't extend the 8 months. Miss it and you wait for the General Enrollment Period and may pay a penalty: 10% of the standard Part B premium for each full 12 months you went without it, for as long as you have Part B. Part B penalty calculator.

What this calculator assumes

You qualify for Medicare at 65 and aren't already on Medicare because of a disability or kidney failure. The dates follow Medicare's rules; Social Security and Medicare make the official decision. All Medicare enrollment periods.

Questions

When should I sign up for Medicare if I'm turning 65?

In the 3 months before the month you turn 65, if you want coverage from the first day of that month. Your Initial Enrollment Period lasts 7 months: the 3 months before, the month you turn 65, and the 3 months after. Sign up in the month you turn 65 or later and coverage starts the month after you sign up.

Do I have to sign up for Medicare if I'm still working?

Not always. If you or your spouse still work and you have health coverage through that job, you may be able to delay Part B without a penalty and sign up later in a Special Enrollment Period, which ends 8 months after the job or the coverage ends, whichever comes first. COBRA and retiree coverage don't count as job coverage for this. Ask the employer's plan how it works with Medicare.

What if my birthday is on the first of the month?

Medicare treats you as turning 65 the day before your birthday, so the month before your birthday counts as the month you turn 65. Your enrollment window and coverage start one month earlier. Someone born July 1 can get coverage from June 1.

Updated November 7, 2026. Sources: Medicare.gov, When does Medicare coverage start?; CMS, Medicare General Information, Eligibility and Entitlement Manual, Chapter 2; Medicare.gov, When can I buy a Medigap policy?; Medicare.gov, Avoid late enrollment penalties; Medicare.gov, Joining a plan. General information, not legal or insurance advice. We don't sell insurance.