Can I Contribute to an HSA AND Have Medicare?

Health Savings Accounts offer significant tax advantages for healthcare expenses — but those benefits come with strict eligibility rules, and Medicare enrollment changes everything. This is one of the most common questions we get, and the answer is more nuanced than a simple yes or no.

The Short Answer

Once you enroll in any part of Medicare — Part A, Part B, or Part D — you can no longer contribute to an HSA. Your final eligible contribution month is the month before your Medicare coverage begins.

That said, money already sitting in your HSA is yours to keep and use tax-free for qualified medical expenses, including many Medicare costs.

The 6-Month Retroactive Part A Rule

Here's where people get into trouble without realizing it. When you delay Medicare enrollment past 65 and apply later, Medicare Part A can be backdated up to six months (though never before your 65th birthday).

That means if you were still contributing to your HSA during that retroactive window, those contributions are now considered "excess" — and the IRS will penalize you for them.

A Real-World Example

Say you turned 65 in April 2024 but didn't apply for Medicare until December 2025. When you apply, Medicare backdates your Part A coverage to June 2025 — six months prior. Any HSA contributions you made from June 2025 onward are now excess contributions.

• May 2025 → Your final eligible HSA contribution month
• June 2025 → Retroactive Part A begins
• December 2025 → You apply for Medicare (backdated to June)

Contributions made June through December would need to be corrected to avoid a 6% penalty.

How to Fix Excess Contributions

If you find yourself in this situation, there are three steps to correct it:

1. Request a withdrawal of the excess contributions and their associated earnings before you file your taxes.
2. Report the correction on IRS Form 8889 to document the excess and avoid the 6% penalty.
3. Remember that your existing HSA balance is still usable — Medicare premiums, deductibles, copays, and many other qualified expenses are fair game.

Key Takeaways

• Stop HSA contributions the month before any Medicare coverage begins.
• If delaying Medicare past 65, be aware that Part A can be backdated up to 6 months when you do apply.
• Use IRS Form 8889 to document any corrections.
• Your existing HSA funds remain available and valuable in retirement.

The timing here is genuinely tricky. If you're approaching 65 and still contributing to an HSA, talking through your Medicare enrollment timing with a licensed agent before you enroll can save you from a costly mistake.