You're turning 65, you're still working, and you want to keep your job's health plan. Whether you have to sign up for Medicare now comes down to one thing: how many people your employer has. For many people working past 65 at a larger company, the answer is no, and skipping Part B saves you a monthly premium for as long as that job coverage holds.

In This Guide

Do You Have to Sign Up for Medicare If You're Working Past 65?

The short answer? Not necessarily. If you're still working past 65 and you have real coverage through your job, you may be able to hold off on Medicare Part B without paying for it a day sooner than you need to.

That hold depends on one number: the size of the employer providing your coverage, whether it's your own job or your spouse's job that carries the plan. Get that detail right and the rest of your timing falls into place.

So before you do anything, find out one thing: does the employer behind your health plan have 20 or more employees, or fewer? Your benefits or human resources office can tell you in about two minutes.

The 20-Employee Rule: Who Pays First

Here's the rule the whole decision hangs on. When you have both Medicare and a job-based group health plan, one of them pays your bills first and the other picks up what's left. Which one goes first depends on the employer's size.

If the employer has 20 or more employees, the group health plan pays first and Medicare pays second. Because that job coverage is still doing its job, you can put off enrolling in Part B (and premium Part A) without a late enrollment penalty for as long as you stay covered by that current employer plan. That's why so many people who work past 65 simply keep their work insurance and skip Part B for now.

If the employer has fewer than 20 employees, it flips: Medicare generally pays first, and the small-employer plan pays second. That changes everything about your timing, and we'll get to it below.

The point is that "who pays first" isn't a technicality. It's the thing that tells you whether waiting on Medicare is safe or a costly mistake.

What to Do About Part A and Part B When Working Past 65

Medicare comes in parts, and you don't have to treat them the same way. The two that matter here are Part A (hospital insurance) and Part B (the part with a monthly premium that covers doctors and outpatient care).

Part A is usually free, so most people just take it. If you've worked and paid Medicare taxes for about 10 years, your Part A premium is $0. Since it costs nothing, plenty of people sign up for premium-free Part A at 65 even while they keep working and stay on the job plan. You can also delay premium Part A along with Part B if that fits your situation.

Part B is where the real decision lives. Part B carries a monthly premium ($202.90 for most people in 2026), so every month you delay it while you're properly covered is a month you don't pay that premium. As long as your employer has 20 or more employees and you keep that coverage, delaying Part B doesn't trigger a penalty.

One thing worth checking with your own benefits office: how your specific plan works with Medicare, and whether a Health Savings Account is in the picture, since signing up for Medicare affects HSA contributions. Your plan administrator can walk you through your particular setup.

When the Job Ends: Your 8-Month Special Enrollment Period

Delaying Part B only works while the job coverage lasts. So the question becomes: what happens when you finally retire, or the coverage ends?

That's what the Special Enrollment Period is for. When the job ends or the group health plan coverage ends, whichever comes first, you get an 8-month window to sign up for Part B without a late enrollment penalty. Enroll inside that window and you're treated as if you signed up on time.

A word of caution, because this is where people get burned. The 8-month clock is tied to active, current employment coverage. Retiree coverage and COBRA (Consolidated Omnibus Budget Reconciliation Act) are not the same thing as coverage from a current job, so don't assume they keep the window open. If you're winding down work, treat the Part B enrollment as something to handle right away, not something to circle back to later.

What If Your Employer Has Fewer Than 20 Employees?

This is the situation that catches people off guard, so read it closely if you work for a small company. When the employer has fewer than 20 employees, Medicare generally pays first and the group plan pays second.

Why that matters: if Medicare is your primary payer and you don't enroll at 65, the small plan expects Medicare to have paid the first share, and you can be left with a gap in what's covered. So in a small-employer situation, you'll typically want to sign up for Medicare at 65 rather than delay it.

Small-group plans vary, so confirm with your plan how it coordinates with Medicare before you decide. But the default assumption for a company under 20 employees is: enroll on time.

Frequently Asked Questions

Do I have to sign up for Medicare at 65 if I'm still working?

Not always. If your health coverage comes from an employer with 20 or more employees, that plan pays first and Medicare pays second, so you can delay Part B without a late penalty while you stay covered. If the employer has fewer than 20 employees, Medicare usually pays first, so you'll generally want to enroll at 65.

Can I delay Medicare Part B while I'm working past 65?

Yes, if your job coverage is from an employer with 20 or more employees and it's still active. You can put off Part B with no late enrollment penalty for as long as you keep that coverage, then sign up during your 8-month Special Enrollment Period once the job or the coverage ends.

Should I take Part A if I'm still working?

For most people Part A costs nothing after about 10 years of paying Medicare taxes, so it's common to take premium-free Part A at 65 even while working. You can also delay premium Part A if you prefer. If you contribute to a Health Savings Account, check with your benefits office first, because enrolling in Medicare affects HSA contributions.

What happens to my Medicare window when I retire?

When your current-employment coverage ends, an 8-month Special Enrollment Period opens for you to sign up for Part B penalty-free. Keep in mind the window is tied to active job coverage, so retiree coverage and COBRA don't count as current employment for this purpose.

My spouse's job provides our coverage. Which employer size counts?

The size of the employer that actually provides the coverage is what matters. If you're covered through your spouse's current job, it's that employer's headcount, 20 or more versus fewer than 20, that decides whether you can delay Part B.

Learn More

MedicareWhen to Sign Up for Medicare: Enrollment Periods and Late PenaltiesWhen to sign up for Medicare without a lifelong penalty: the 7-month Initial Enrollment Period, working past 65, the GEP, and what each late penalty costs. MedicareMedicare Special Enrollment Periods: The Life Events That Reopen Your WindowThe life events that let you enroll in or switch Medicare outside the usual windows: retiring past 65, losing Medicaid, moving, a plan exit, and the COBRA trap. MedicareOriginal Medicare vs. Medicare Advantage: How to ChooseCompare original Medicare vs Medicare Advantage on cost, networks, the $9,250 cap, and switching back. A neutral 2026 side-by-side to help you choose.

Find personalized help deciding whether to take Medicare or keep your employer plan past 65 at brevy.com.

The information on Brevy.com is for educational purposes only and is not a substitute for professional legal, financial, or medical advice. Rules vary by state and program and change frequently. Always verify with the relevant agency or a qualified professional. Brevy is not a law firm, financial advisor, or healthcare provider.

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Brevy Care Team

Expert eldercare guidance from Brevy's team of healthcare professionals and researchers.