Turning 65? Find your exact Medicare sign-up window.
You have a seven-month window to sign up, and it is built around your birthday. Enter your date of birth and I'll calculate your personal dates: when your window opens, when it closes, when your coverage starts, and when your Medicare Supplement deadline falls.
Nothing is stored and no email address is required. It runs entirely in your browser.
Last reviewed: September 2026. The enrollment windows, deadlines and penalty rules on this page were checked on that date. Rules change — always confirm your own dates at Medicare.gov.
The seven months, in order
Three months before
Your window opens. Enroll now and your coverage starts the first day of your birthday month — no gap.
Your birthday month
Still inside the window, but your coverage start date begins to slip.
Three months after
The final month of your window. Once it closes, a late-enrollment penalty can apply and your coverage start date can be delayed by a month or more.
Separately, and just as important: your Medicare Supplement (Medigap) Open Enrollment Period is a different clock — a one-time six-month window that starts the first month you have Part B and are 65 or older. During those six months an insurer must sell you any Medigap policy it offers, with no health questions. Kansas has no Medigap birthday rule, so after that window insurers here can underwrite you. Both deadlines are in the results below.
Your date of birth
Your Medicare dates
Your sign-up window opens
Three months before your birthday month. This is the earliest you can enroll.
Your sign-up window closes
Three months after your birthday month. Enrolling this late can delay your coverage.
Best time to enroll
Enroll during these months and your coverage starts on the first day of your birthday month.
Medigap deadline
Your one-time six-month Medicare Supplement Open Enrollment Period. After this, Kansas insurers can ask about your health.
Why the Medigap date matters more in Kansas
Kansas does not have a Medigap "birthday rule," so unlike some states there is no annual no-questions-asked window to change Medicare Supplement plans later. Your six months is the only guaranteed shot — and it does not come back.
Important
This is a general educational estimate based on how the Initial Enrollment Period works. It is not an official determination and it does not account for every situation — if you or your spouse still has employer coverage, different rules may apply to you. Confirm your actual dates with the Social Security Administration or 1-800-MEDICARE before you rely on them.
Want me to check this against your situation?
If you or your spouse is still working, or you're already on Medicare and thinking about changing, the dates above may not tell the whole story. That's a fifteen-minute conversation, and it's free.
The rule behind the dates
Your Initial Enrollment Period is seven months long: the three months before the month you turn 65, the month you turn 65, and the three months after. That is the only window in which you can enroll in Part A and Part B with no possibility of a late-enrollment penalty.
Two details almost nobody explains, and both are in the dates above:
- Enrolling early gets you covered sooner. Sign up during the three months before your birthday month and coverage begins on the first day of your birthday month — no gap. Wait until your birthday month or later and your start date slides, which can leave you uncovered for a month or more.
- Born on the first of the month? Medicare treats you as turning 65 in the previous month, which shifts your entire seven-month window one month earlier. That's why the calculator asks for the day.
And the penalty for missing the window is permanent: 10% added to your Part B premium for every full 12-month period you were eligible but not enrolled. In most cases that surcharge stays with you as long as you have Part B.
Still working at 65 and covered by an employer plan? You can often delay Part B without penalty — but the rules depend on the size of your employer and how your coverage works. That's worth checking before you decide, and it's the conversation I have most often with people in your position.
Want me to walk you through it?
Bring your dates and your questions. Thirty minutes, free, and no obligation to enroll in anything.