If you’re turning 65 and you’re still working, here’s the question I get more than almost any other: “Do I sign up for Medicare now, or do I wait?”
The honest answer is — it depends. And the biggest factor is one thing: the size of the employer you’re working for. Let me break it down — and give you a bit more of the “why” behind each piece than I can fit into a short video.
A quick note before we dive in: this post is educational, not personalized advice. Medicare rules have a lot of edge cases, and your situation may involve details this article doesn’t cover. Always confirm specifics with your employer’s benefits team, Medicare.gov, or a licensed advisor before making a decision.
Part A: The Free One (With a Catch)
Let’s start with Part A, which covers inpatient hospital stays, skilled nursing care, hospice, and some home health care. For most people, Part A is premium-free because you’ve paid into it through payroll (FICA) taxes for at least 10 years — typically 40 quarters — of work history. Because it doesn’t cost anything, most people take it at 65 even if they’re still working, since there’s no real financial downside to also carrying it alongside employer coverage.
If you haven’t worked the required quarters (or your spouse hasn’t), Part A isn’t automatically free — in 2026, those who have to pay a premium for Part A pay somewhere between roughly $311 and $565 a month, depending on how many quarters they’ve paid in.
Here’s the exception that trips people up: if you or your spouse are contributing to a Health Savings Account (HSA), enrolling in Part A can create a real problem. When you sign up for Medicare after your 65th birthday, Part A enrollment is applied retroactively — up to six months back (but not earlier than your 65th birthday). And once you’re enrolled in any part of Medicare, you’re no longer allowed to contribute to an HSA. If you (or your employer) kept contributing during that retroactive window without realizing it, you could end up with excess HSA contributions that the IRS considers a tax issue. So if HSA contributions matter to you, stop contributing a few months before you plan to enroll, and talk to your tax advisor before you enroll — not after.
Part B: Where the Real Decision Lives
Now, Part B — this covers outpatient care, doctor visits, preventive services, and durable medical equipment. It’s the one that actually costs a monthly premium, and it’s where the real decision lives.
For 2026, the standard Part B premium is $202.90 a month for most people (higher-income beneficiaries pay more under IRMAA, the income-related adjustment). That premium matters because if you enroll late without a qualifying exception, the penalty is permanent — it’s added to your premium for as long as you have Part B, for the rest of your life.
Here’s the rule that matters most: how many employees does your employer have?
If your employer has 20 or more employees: your group health plan is considered primary, and Medicare would be secondary. In this case, you can generally delay Part B without a late enrollment penalty, as long as you keep that employer coverage. When you eventually retire or lose that coverage, you get a Special Enrollment Period (SEP) — typically 8 months from when the job or coverage ends — to sign up for Medicare penalty-free. Check your specific plan for details, since some plans coordinate with Medicare differently than others.
If your employer has fewer than 20 employees: Medicare becomes the primary payer, even while you’re still working. In that case, delaying Part B usually isn’t a good idea — your employer plan may pay very little without Medicare backing it up, and you could face a permanent late enrollment penalty down the road. That penalty works out to roughly 10% of the standard premium for every full 12-month period you were eligible but didn’t enroll. So if you delayed two years, you’d be looking at an extra 20% added to your Part B premium — for as long as you’re on Medicare.
If you miss your window entirely and don’t qualify for a SEP, your only option is the General Enrollment Period, which runs January 1 through March 31 each year — and even then, coverage doesn’t start immediately, and the late penalty still applies.
So step one, always: call your HR or benefits department and ask directly, “How many employees does our company have, and how does our health plan coordinate with Medicare?” Get that in writing if you can — this single fact drives almost everything else in your decision.
A Real-World Scenario: Meet Mark
Let me walk you through a scenario I see all the time, because it adds a layer people don’t think about — and it’s a great example of why “what’s best for me” and “what’s best for my household” aren’t always the same question.
Let’s say we have a gentleman — I’ll call him Mark. Mark is turning 65. He works full-time for a large company, well over 20 employees, so we already know he can delay Part B without penalty. Easy, right?
Not so fast. Mark’s family is on his employer plan too — his wife, who is 62 and not yet Medicare-eligible, and two dependent kids. That whole family is covered under Mark’s employer-sponsored plan.
Here’s the layer people miss: if Mark drops his own coverage and moves to Medicare, what happens to his wife and kids? In many cases, dependents cannot stay on an employee’s group plan if the employee themselves is no longer enrolled in it — most employer plans are structured so the employee is the “subscriber,” and dependent coverage is tied to that subscriber remaining active on the plan. Some employer plans do allow dependents to stay enrolled independently — but many don’t, and it varies plan by plan, so this isn’t something to assume either way.
So for Mark, the decision isn’t just “what’s right for me at 65.” It’s “what happens to my whole family’s coverage if I make this move.” If Mark drops his group coverage for Medicare and his wife and kids lose access to that plan, they’d need to look at other options for the family — most likely ACA marketplace coverage, since Mark’s wife at 62 isn’t yet Medicare-eligible and the kids likely wouldn’t qualify for Medicare either. Marketplace premiums for a spouse and two dependents could easily run more per month than what Mark saves by moving off the employer plan early, especially without an employer subsidizing part of the cost.
In a case like this, Mark likely takes premium-free Part A — since it doesn’t affect the family plan — and delays Part B, keeping the employer plan fully intact for himself and his family, until either he retires or his wife turns 65 and becomes Medicare-eligible, at which point the whole family’s coverage picture changes and is worth revisiting.
Don’t Forget: Creditable Coverage
One more thing: even if you delay Part B, you want to confirm your employer’s prescription drug coverage is considered “creditable” — meaning Medicare considers it as good as or better than its standard Part D plan, on average, for the whole group of people covered by it.
Your employer is required to send you a notice each year (usually every fall, before Medicare’s Annual Enrollment Period) telling you whether your drug coverage is creditable. Keep that notice — every single year’s copy, not just the most recent one.
Here’s why it matters: if you ever do enroll in a Part D plan later, you may be asked to prove you had continuous creditable coverage from the time you were first eligible for Medicare. Without that proof, you could face a Part D late enrollment penalty — calculated as 1% of the national base beneficiary premium for every month you went without creditable coverage, added to your monthly premium for as long as you have Part D. It’s a smaller monthly number than the Part B penalty, but it’s also permanent, and it adds up over the years the same way.
Bottom Line
If you’re turning 65 and still working, don’t just default to signing up — and don’t just default to waiting either. Find out your employer’s size, check how your coverage coordinates with Medicare, and if you have a spouse or dependents on your plan, factor their coverage into the decision too.
This is exactly the kind of thing I help people work through every day — so if you’re staring down 65 and you’re not sure which way to go, reach out. Let’s map it out together before you make a move you can’t undo.
