Working Past 65? What That Means for Your Medicare Enrollment

More people are working past 65 than in years past, and one of the most common questions we hear is some version of: "Do I actually need to do anything with Medicare right now?" The honest answer is: it depends mostly on the size of your employer and the coverage you already have.

The general rule: employer size matters

If you have group health coverage through an employer with 20 or more employees, that coverage is generally considered primary, and you can typically delay enrolling in Part B without a penalty for as long as that employment and coverage continues.

If your employer has fewer than 20 employees, the rule usually works differently — Medicare often becomes the primary coverage at 65 regardless of whether you're still working, which means delaying Part B enrollment can leave real gaps. This is exactly the kind of detail worth confirming with your specific employer's plan, since it isn't always obvious from the outside how a plan is classified.

What about Part A?

Part A is usually premium-free for people who qualify based on work history, so many people enroll in Part A at 65 even while still working and keeping employer coverage. One caution worth knowing: enrolling in Part A can affect your ability to continue contributing to a Health Savings Account (HSA), if you have one — that's worth checking before you enroll if HSA contributions matter to you.

The Special Enrollment Period

When you eventually retire, or your employer coverage ends for any reason, you generally get an 8-month Special Enrollment Period to sign up for Part B without a late enrollment penalty. That window starts the month after your employment or your coverage ends — whichever happens first. Missing that window is where the penalty risk comes in.

How the penalty concept works

The Part B late enrollment penalty, when it applies, is generally calculated as a percentage added to your monthly premium for each full 12-month period you could have had Part B but didn't — and it's typically permanent, not a one-time fee. The exact dollar amount changes because it's based on the current premium, but the mechanic — a percentage penalty tied to how long you waited — stays consistent. The Part D late enrollment penalty works on a similar percentage-based idea, tied to how long you went without creditable drug coverage.

The way to avoid either penalty is straightforward: keep creditable coverage in place without a gap, and enroll during your Initial Enrollment Period or the Special Enrollment Period that follows qualifying employer coverage.

The bottom line

Working past 65 doesn't mean Medicare disappears from your radar — it just changes the timing. The size of your employer's plan is the single biggest factor in figuring out what you need to do now versus what you can safely defer.