The Part B Special Enrollment Period: your 8-month deadline
Worked past 65 with health coverage from your job or your spouse's? You can sign up for Part B late with no penalty, but only inside an 8-month window. Here's how to find your exact deadline.
Your deadline calculator
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- Jan2027month 2
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No gap in coverage: apply before your coverage ends, or during Dec 2026, and pick December 1, 2026 as your Part B start date on Form CMS-40B.
Do you qualify?
You qualify for the Special Enrollment Period if all of these are true:
- You are 65 or older and already have Part A.
- Since turning 65 you had health coverage from an employer or union group health plan.
- That coverage came from someone's current job: yours, or your spouse's.
- The job or the coverage ended less than 8 months ago, or is about to end.
| Coverage | Counts? |
|---|---|
| Your employer's group health plan while you are working | Yes |
| Your spouse's employer plan while your spouse is working | Yes |
| COBRA | No. Not coverage from current work. It does not move your deadline. |
| Retiree health coverage from a former employer | No |
| VA health care | No |
| A Marketplace plan or other insurance you bought yourself | No |
COBRA is the most expensive mistake
Small employer (fewer than 20 employees)? Medicare usually pays first, so the plan may expect you to have Part B already. Ask your plan before you delay. People with End-Stage Renal Disease can't use this Special Enrollment Period.
How the 8 months are counted
The window starts the month after your job ends or your coverage from that job ends, whichever happens first, and lasts 8 months. Social Security must have your application by the last day of month 8.
Example: Walt
Walt's last day at work was July 17, 2026, and his coverage ran to July 31, 2026. Both ended in July, so his 8 months run from August 2026 to March 2027. His deadline is March 31, 2027. He applied in early August so Part B could start on August 1, with no gap.
Three traps
- The job ends before the coverage. Last day of work June 30, coverage to July 31? The clock starts from June, so the deadline is February 28, not March 31.
- COBRA or severance coverage. Coverage that continues after the job ends is not coverage from current work. Use the month the job ended.
- Coverage through your spouse. Use your spouse's job and plan dates. If your spouse retires or drops you from the plan, your clock starts then.
How to sign up in your Special Enrollment Period
- Send the CMS-L564 to your employerYour employer fills in Section B to confirm your coverage. Give HR a reply date. How to fill in the CMS-L564.
- Fill in the CMS-40BAnswer Yes to the job coverage question and choose a start date. How to fill in the CMS-40B.
- Submit online, by fax or by mailOnline on Social Security's Part B only page is fastest. Fax or mail goes to your local office.
- Then set up drug coverage and MedigapYou have 2 full months after creditable job drug coverage ends to join a Part D plan without a penalty, and a 6-month Medigap open enrollment period from the month Part B starts.
Missed your 8 months?
- General Enrollment Period: sign up from January 1 to March 31. Part B starts the month after you sign up. A late penalty may apply: calculate it here.
- Misled by your employer, plan or a broker? Since 2023 there are "exceptional conditions" windows. Apply with Form CMS-10797 and proof of what you were told, and you may avoid both the wait and the penalty.
- Misled by Social Security or another federal employee? Ask for equitable relief in writing.
Includes the deadline worksheet, both filled forms, the HR letter, and Bonus #3 if you think you've missed it.
Filled-in examples of Forms CMS-40B and CMS-L564, plus a plan for when your old employer is slow, gone, or won't sign.
- Filled CMS-40B example
- Filled CMS-L564 example for your employer
- If your employer won't sign or is gone
- 8-month deadline worksheet
- Plus 3 free bonuses, including the Letter to Your Employer's HR
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The official forms are free from ssa.gov and cms.gov. The kit is the help filling them in and proving your case. See everything inside
Questions people ask
How long is the Part B Special Enrollment Period?
8 months. It starts the month after your job ends or your coverage from that job ends, whichever happens first.
Does COBRA extend my Special Enrollment Period?
No. COBRA is not coverage based on current employment. Your 8 months keep running while you're on COBRA, and if you wait for COBRA to end you will usually miss your window.
Can I sign up before my coverage ends?
Yes. You can sign up any time while you're still covered by a current job, and choose a Part B start date up to 3 months later. That's the best way to avoid a gap.
What forms do I need?
Form CMS-40B (your request for Part B) and Form CMS-L564 (your employer's proof of coverage). Or apply online on Social Security's Part B only page and upload the proof.
What if I missed the 8 months?
You can usually only sign up from January 1 to March 31, with Part B starting the month after, and a late penalty may apply. If an employer, plan or broker misled you, you may qualify for an exceptional-conditions window with no penalty.
Does the Special Enrollment Period also cover Part D?
Part D has its own rule. If your job's drug coverage was creditable, you have 2 full months after it ends to join a Part D plan with no penalty.