Free tool
When is my Medicare sign-up window?
Enter your date of birth and get your exact 7-month window, the date coverage can start, and whether the first-of-the-month rule shifts everything a month earlier for you.
What this can't do: Uses your birthday only. If you have employer coverage, your window may be different.
Why the window is 7 months and not 3
Most people picture a deadline on their 65th birthday. It isn't one. The window opens 3 months before the month you turn 65 and stays open for 3 months after it, which is 7 months in total.
The part that matters is where inside the window you sign up. Only the first 3 months get you coverage that starts the day you turn 65. Sign up later and you're still on time, but there's a gap before coverage begins.
If you're still working at 65 with coverage through that job, different rules apply and you may be able to delay Part B without any penalty. That's covered in Still working at 65. If you want the whole picture in plain language, start with When do I actually sign up for Medicare?
Nothing you type here leaves your device
This tool runs entirely inside your own browser. What you enter is never sent to us, never stored, and never shared. You can disconnect from the internet after the page loads and it will still work. That is deliberate: we tell people never to hand their Medicare number to a website, so this site had better not be one that asks.
Where these numbers come from
These are the 2026 amounts. CMS usually publishes the next year's figures in mid-November and SSA in October; after that, check the source links before relying on a result.
Free, official help with your own decision
This tool does arithmetic on published rules. For a decision about your own coverage, use the official sources. They're free and they don't sell anything.
- Medicare.gov The official government site to compare plans and check coverage yourself.
- SHIP: free local counseling Your State Health Insurance Assistance Program: free, unbiased Medicare help.