Special Enrollment Period Finder and Calculator

Key takeaway: A Special Enrollment Period lets you sign up for Medicare outside the standard windows without a penalty — but only if your triggering event is on the approved list, and COBRA specifically does not qualify.

What this helps you decide

• Whether the life event you just experienced actually qualifies you for a Special Enrollment Period
• How long your SEP window lasts after the qualifying event and when the clock starts ticking
• Which parts of Medicare your SEP applies to — Part A, Part B, Part D, or a Medicare Advantage plan change
• What to do if your event doesn't qualify so you can plan around the next available enrollment window

Who this is for

• Someone who just retired or lost their job and needs to enroll in Medicare without waiting for the next General Enrollment Period
• A person who recently moved out of their Medicare Advantage plan's service area and needs to switch plans
• Anyone who recently lost Medicaid or other low-income subsidy coverage and needs to get Part D in place
• A family member trying to understand whether a parent's recent life change (losing employer coverage, moving to a nursing facility) triggers an enrollment window

Example results

Example 1 — Lost employer coverage after retirement. You retired in March 2026 after working for a company with 25 employees, and your employer coverage ended April 30, 2026. Your 8-month SEP for Part B started May 1, 2026, and runs through December 31, 2026. As long as you enroll during that window, you owe no late penalty — no matter that you're well past your original IEP. This is the most common SEP trigger. Important: if you take COBRA after leaving your job, that does not extend the 8-month window. Your SEP clock started when active employment ended, not when COBRA runs out. If you let COBRA run for 18 months and then try to enroll in Part B, you'll be outside your SEP and face a permanent penalty.

Example 2 — Moved out of your Medicare Advantage plan's service area. You were enrolled in a Medicare Advantage plan based in Phoenix, Arizona. In April 2026 you moved to Nashville, Tennessee, where your plan has no coverage. Moving to a new address that's outside your plan's service area triggers a plan-change SEP. You have two months from the date you moved to switch to a new Medicare Advantage plan or return to Original Medicare (Parts A and B) plus a standalone Part D plan. Missing this 2-month window means you're stuck with a plan that doesn't cover your new location until the next Annual Enrollment Period in October.

Example 3 — Lost Medicaid eligibility. You were covered by your state's Medicaid program, but your income changed in February 2026 and you were disenrolled. Losing Medicaid triggers a Part D SEP, giving you a window to enroll in a standalone prescription drug plan without penalty. The SEP for Part D after losing Medicaid lasts for 63 days from the loss of coverage. After 63 days without creditable drug coverage, every additional month accrues a Part D late penalty of 1% of $38.99. Twelve months without coverage, for example, would add $4.68 to your monthly Part D premium permanently.

Sample scenarios

Scenario	Input	Result
Retired, lost employer coverage	Active employment ended April 2026	8-month SEP for Part B: May 1 – December 31, 2026. No penalty if enrolled by then.
Moved out of MA plan area	Relocated April 2026	2-month SEP to change MA plans or switch to Original Medicare. Deadline: June 30, 2026.
Lost Medicaid in February 2026	Disenrolled from Medicaid	63-day SEP for Part D. Enroll by ~April 4, 2026 to avoid penalty.
COBRA after job loss	Left job, chose COBRA continuation coverage	COBRA does NOT extend SEP. 8-month Part B window started when job ended, not when COBRA ends.

What to do next

• Identify the date your qualifying event occurred — this is the start of your SEP clock. Write it down and calculate your deadline before doing anything else.
• Contact Social Security (1-800-772-1213) or your State Health Insurance Assistance Program (SHIP) counselor to confirm your event qualifies before assuming you're in an SEP window.
• If your trigger was losing employer coverage, gather documentation: a letter from your employer confirming coverage end date, or an COBRA election notice. You'll need this when enrolling.
• If your event does NOT qualify for an SEP, check the General Enrollment Period (January 1–March 31) or Annual Enrollment Period (October 15–December 7) timelines so you can plan ahead without incurring avoidable gaps.

Key facts

• The most common Special Enrollment Period for Part B is triggered by losing coverage from a current employer (yours or your spouse's) with 20 or more employees. This SEP lasts 8 months from the end of employment or coverage, whichever comes first.
• COBRA, retiree coverage, and VA benefits do not count as current employer coverage for SEP purposes. Relying on these after leaving a job does not pause or restart your enrollment window.
• Different Medicare parts have different SEP lengths: Part B typically offers an 8-month SEP after losing employer coverage, while Part D and Medicare Advantage plan-change SEPs are often shorter — as brief as 2 months for plan-area moves or 63 days for loss of Medicaid.

Related decisions

• Employer coverage vs. Medicare — Compare the cost of keeping employer coverage versus switching to Medicare.
• COBRA vs. Medicare — Understand why COBRA doesn't extend your enrollment window and when each makes sense.
• When should I sign up for Medicare? — Map out the full enrollment timing decision for your situation.
• Late enrollment penalty checker — Calculate what you'd owe if your window has already passed.