Working Past 65? Here's Your Medicare Guide

Sixty-five shows up whether you’re ready for it or not. And if you’re still working, still covered by your employer’s health plan, and suddenly getting Medicare signup reminders in the mail, you’ve probably got that nagging feeling you’re supposed to do something but have no idea what. I’ve watched that confusion turn into genuinely expensive mistakes, and I’d rather you not make them.

Let me be direct: the rules around Medicare and active employment coverage are genuinely complicated, and most of the generic advice floating around online doesn’t account for the details that actually matter to your specific situation. So let’s slow down and work through this together.

You Have More Time Than You Think (Probably)

Most people panic about this one thing: the standard Medicare enrollment window is the 7-month Initial Enrollment Period (IEP) centered on your 65th birthday. Miss it, the story goes, and permanent late-enrollment penalties follow. True in some situations. But if you’re still working and covered by a qualifying employer health plan, the rules are different. Much more forgiving, actually.

Work for a company with 20 or more employees and you’re enrolled in their group health plan? Your employer plan is primary. Medicare plays secondary. In that scenario, you can delay Part B (doctor visits and outpatient care) without any penalty. You get a Special Enrollment Period (SEP) that lasts 8 months after you stop working or your employer coverage ends, whichever comes first.

Part A is different. Hospital stays, skilled nursing facility care, home health services, that’s Part A. If you’ve worked at least 10 years (40 quarters) paying Medicare taxes, Part A is premium-free. Most people in this situation sign up for Part A at 65 even while still working, because it costs nothing and could cover a hospital stay if your employer plan doesn’t. There’s a meaningful exception I’ll get to in a moment, but generally: sign up for Part A, hold off on Part B if you’re still actively covered through a large employer.

Companies with fewer than 20 employees flip this completely. Medicare becomes primary even if you’re still working, which means your small employer plan is basically supplemental. You really do need both Part A and Part B at 65, or you’re leaving your primary coverage behind. Some small employers won’t tell you this. I’ve talked to people who found out the hard way, after a claim was denied, that their small-group plan had been paying as if Medicare was primary for months.

The HSA Trap Nobody Warns You About

Helpful resource: AUVON Weekly Pill Organizer with AM/PM Compartments is a top-rated option for this. (As an Amazon Associate this site earns from qualifying purchases.)

This catches a lot of high earners off guard. I wish someone had flagged it for me years ago.

If you or your employer contributes to an HSA (Health Savings Account), enrolling in any part of Medicare, including Part A, makes you ineligible to contribute anymore. The moment Medicare kicks in, contributions must stop or you’ll owe taxes and a penalty.

What trips people up is the look-back rule. When you finally enroll in Part A after delaying, Medicare can make your coverage retroactive for up to 6 months. So if you enrolled in October and contributions were still going into your HSA in May, you owe taxes on those contributions even though you thought you were fine at the time.

Here’s the practical fix: if you want to keep contributing to your HSA past 65, delay all parts of Medicare, including Part A, and stop HSA contributions at least 6 months before you plan to enroll in Part A. Yes, that means giving up those tax-advantaged contributions early. Still often worth it if you’ve got a high-deductible plan and a solid HSA balance building up, but you need to run those numbers on purpose, not just drift into it.

The Centers for Medicare & Medicaid Services has detailed guidance at cms.gov, but honestly the IRS publication on HSAs is where the enrollment timing rules are really spelled out. If your accountant hasn’t flagged this, bring it up yourself.

Part D: The Prescription Drug Coverage Question

Part D is Medicare’s prescription drug coverage. Unlike Part B, the late enrollment penalty for Part D depends on how long you went without “creditable” drug coverage, coverage from another source that’s at least as good as the standard Part D benefit. Most large employer plans qualify as creditable, so you can safely delay Part D enrollment while still working and covered.

When you leave your employer and enroll in Part D, get a letter from your employer confirming your drug coverage was creditable for the period you were enrolled. Keep that letter. Medicare may ask for it, and without it you could face penalties that stick with you permanently.

Part D premiums vary significantly by plan and region right now. Use Medicare’s plan comparison tool at Medicare.gov to see what’s available in your zip code and compare drug formularies against your actual medication list. Don’t assume the cheapest premium is the best deal; do the math on your specific prescriptions.

Making the Decision: What Actually Matters

Here’s my honest opinion: this isn’t a decision to make based on a generic checklist. It depends on four things specific to your situation.

First, your employer’s size. Twenty employees is the dividing line. Know which side you’re on.

Second, the quality of your employer coverage. If your group plan has a $6,000 deductible and mediocre network, Part B at $185 a month (the standard 2026 premium) might actually be worth adding as a secondary payer to reduce your out-of-pocket costs. Run an actual cost comparison before assuming your employer plan is the better deal just because it’s free.

Third, whether you have an HSA and how much it matters to you. The tax savings on HSA contributions can be substantial, especially if you’re in a high tax bracket. That’s worth delaying Medicare enrollment over in some cases.

Fourth, your health situation. If you’re managing a chronic condition or anticipate significant healthcare use, having Medicare as a secondary payer could genuinely save you money even if you’re not technically required to enroll yet.

AARP’s Medicare resource center at aarp.org has a good employer coverage coordination tool that walks through some of these scenarios. Free to use.

One thing I’d push back on: the idea that you should always delay Medicare if you can. Often true, but not always. I’ve seen people carrying employer coverage with high deductibles and limited networks who would’ve been better off enrolling in Part B and letting Medicare pick up what the employer plan left behind. “You can wait” and “you should wait” are two different things.

When You Finally Do Stop Working

The 8-month Special Enrollment Period starts the day your employment ends or your employer coverage ends, whichever happens first. Not the day you request Medicare enrollment, the day coverage ends. This matters because you want to time your Medicare enrollment so your new coverage starts without a gap.

A common mistake: people assume the SEP starts when they retire, so they figure they have 8 months to figure it out. Then they realize Medicare Part B doesn’t start immediately after you apply; there’s a processing lag. Apply a few months before your employer coverage ends if you can. Aiming for January 1 Part B coverage? You generally need to apply by October 1 of the prior year.

COBRA is not creditable coverage for avoiding the Medicare late enrollment penalty. If you leave work, turn down Part B, and take COBRA instead, the clock on penalty-free enrollment doesn’t pause. That’s one of the most expensive misconceptions I come across. COBRA can run $700 or $800 a month for a single person and it doesn’t protect you from Medicare penalties. It’s almost never the right bridge strategy.

The real takeaway: “I’m still working” doesn’t mean you can ignore Medicare at 65. It means you have options, but those options come with deadlines, conditions, and one genuinely sneaky HSA trap. Get the details right for your specific situation, and don’t rely on what your coworker did. Their employer, their health, and their finances aren’t yours.

This article is for informational purposes only. Medicare rules change annually. Always verify current plan details at Medicare.gov or by calling 1-800-MEDICARE (1-800-633-4227). This site does not sell insurance or recommend specific plans.

Sources

• AUVON Weekly Pill Organizer with AM/PM Compartments
• cms.gov
• aarp.org
• Copper Compression Knee Support Sleeve
• OMRON Platinum Blood Pressure Monitor Upper Arm

Disclosure: As an Amazon Associate, we earn a small commission from qualifying purchases at no extra cost to you. We only recommend products that genuinely support the topics covered in this article.

• Medicare For Dummies (~$22), The definitive consumer guide to Medicare, enrollment windows, Part A/B/C/D, and supplement plans.
• Get What’s Yours for Medicare (~$17), Maximize your Medicare benefits and minimize out-of-pocket costs. Covers Part D drug coverage gaps and Medigap in depth.

Recommended Resources

Disclosure: As an Amazon Associate, we earn a small commission from qualifying purchases at no extra cost to you. We only recommend products that genuinely support the topics covered in this article.

• Medicare For Dummies (~$22), The definitive consumer guide to Medicare, enrollment windows, Part A/B/C/D, and supplement plans.
• Get What’s Yours for Medicare (~$17), Maximize your Medicare benefits and minimize out-of-pocket costs. Covers Part D drug coverage gaps and Medigap in depth.