When do I need to sign up for Medicare?
Enter your birthday and answer two questions. You get your exact 7-month window, the day your coverage would start, and what changes if you are still working. Nothing you enter is saved or sent anywhere.
How the Medicare enrollment window works
Your Initial Enrollment Period is seven months long: the three months before the month you turn 65, that month, and the three months after. When inside those seven months you sign up decides when coverage starts.
- Sign up in the three months before your birthday month, and coverage starts on the 1st of your birthday month. This is the on-time option.
- Sign up during your birthday month or in the three months after, and coverage starts the 1st of the month after you sign up. Since 2023 there is no longer a longer wait for late-window sign-ups, but you can still have a gap.
Three situations that change the answer
Your birthday is on the 1st. Medicare treats you as turning 65 the day before, so your window and your coverage both move one month earlier. Born December 1? Your window runs August through February and on-time coverage starts November 1.
You are still working at 65. If you or your spouse have health insurance from a current employer with 20 or more employees, you can usually delay Part B with no penalty, and you get an 8-month window to sign up once that job or that coverage ends. COBRA and retiree plans do not count, and if you fund an HSA, the timing of Part A matters too. This is the situation where the calculator's answer changes the most, and where a five-minute phone call is worth the most.
You already get Social Security. If you have been receiving Social Security or Railroad Retirement benefits for at least four months before 65, Medicare enrolls you in Part A and Part B automatically, and your card arrives about three months before coverage begins. You can decline Part B if you have coverage from current employment, and the card comes with instructions for that.
For the full walkthrough, see When to Sign Up for Medicare: The 7-Month Window and, if you are still on the job, Working Past 65: Do You Have to Sign Up?
Common questions
When do I need to sign up for Medicare?
Most people sign up during their Initial Enrollment Period, a 7-month window that starts 3 months before the month you turn 65 and ends 3 months after it. To have coverage begin the month you turn 65, sign up during the first 3 months. If your birthday is on the 1st of a month, the whole window moves one month earlier. If you are still working at 65 with health insurance from your or your spouse's current employer, you may be able to delay Part B without a penalty.
What happens if my birthday is on the 1st of the month?
Medicare treats you as reaching 65 the day before your birthday, so your coverage and your enrollment window both move one month earlier. Someone born December 1 has a window that runs August 1 through the last day of February, and on-time coverage starts November 1. The calculator applies this automatically.
When does Medicare coverage start after I sign up?
Under rules in effect since January 1, 2023: sign up in the 3 months before your 65th-birthday month and coverage starts the 1st of that month. Sign up during your birthday month or the 3 months after, and coverage starts the 1st of the month after you sign up. The same month-after rule applies to the General Enrollment Period, January 1 through March 31.
Can I delay Medicare if I am still working?
Often, yes. If you or your spouse are actively working and you have group health coverage from that employer, and the employer has 20 or more employees, you can delay Part B and get an 8-month Special Enrollment Period once the employment or the coverage ends, whichever comes first. COBRA and retiree coverage do not count. If the employer has fewer than 20 employees, Medicare is primary at 65 and you should enroll during your Initial Enrollment Period. If you contribute to a Health Savings Account, delaying Part A matters too, because Part A backdates up to 6 months when you enroll.
What if I missed my Initial Enrollment Period?
You can sign up during the General Enrollment Period, January 1 through March 31 each year, with coverage starting the 1st of the month after you sign up. A late enrollment penalty of 10 percent of the Part B premium for each full 12-month period you could have had Part B but did not may apply for as long as you have Part B, unless you had qualifying coverage from current employment. Whether that applies to you depends on your history, which is worth a phone call before you assume the worst.
Does this calculator store my birthday?
No. The dates are calculated in your browser and nothing you enter is sent to us or to anyone else. If you choose to add the dates to your calendar or email them to yourself, that happens on your own device.
This calculator is general information based on federal Medicare enrollment rules and is not advice for your specific situation. It does not calculate penalty amounts, disability enrollment dates, or state-specific Medicare Supplement rules. Confirm your dates with Social Security at 1-800-772-1213 or ssa.gov/medicare before making decisions. Tyler Insurance Group is not connected with or endorsed by the United States government or the federal Medicare program. We do not offer every plan available in your area. Currently we represent 6 organizations which offer 158 products in your area. Please contact Medicare.gov, 1-800-MEDICARE, or your local State Health Insurance Program (SHIP) to get information on all of your options.