Once you enroll in any part of Medicare you can no longer contribute to a Health Savings Account, but you can still spend the money you already saved, including on most Medicare premiums. The rules are simple in plain terms: stop putting money in when Medicare starts, and keep using what is already there.
No. Once you are enrolled in any part of Medicare, you are no longer allowed to contribute to a Health Savings Account. This catches a lot of people by surprise, because it does not matter which part you sign up for. Part A alone is enough to end your eligibility to contribute, even though Part A is premium-free for most people and feels like a small step.
The key word is contribute. Losing eligibility does not mean you lose the account or the money in it. You keep your full HSA balance, it stays yours, and you can still spend it tax-free on qualified costs. What changes is that no new money can go in once Medicare begins.
The practical move is to stop your HSA contributions before your Medicare start date. If you are still working past 65 and plan to delay Medicare, you may be able to keep contributing for a while, but only as long as you are not enrolled in any part of Medicare. The moment you enroll, the door on new contributions closes.
Here is the part that trips people up the most. When you enroll in Medicare Part A after age 65, your coverage can be backdated by up to six months. Social Security does this automatically in many cases. So even if you sign up in, say, July, your Part A coverage can be treated as having started six months earlier.
That backdating matters for your HSA. Because you are counted as enrolled in Medicare for those earlier months, any HSA contributions you made during that backdated window were not actually allowed. Contributions you were not eligible to make can trigger a tax penalty, which is the last thing you want from an account meant to save you money.
The safe rule of thumb is to stop your HSA contributions at least six months before you apply for Medicare or Social Security. Giving yourself that cushion keeps the backdated coverage from overlapping with months you were still adding money. If you are unsure about your own timing, this is a good question for a tax advisor before you file.
The good news is that your HSA stays useful well into your Medicare years. You can use the money you already saved to pay several Medicare premiums tax-free. That includes your Part B premium, your Part D drug plan premium, and your Medicare Advantage plan premium. Paying these from your HSA stretches your dollars, because the money was never taxed going in and is not taxed coming out for a qualified expense.
There is one notable exception. You cannot use HSA funds to pay your Medigap, also called Medicare Supplement, premiums. Those supplement premiums are not on the list of qualified expenses, so paying them from your HSA would not be tax-free. It is an easy detail to miss, so keep Medigap off the list when you plan which bills to cover.
Beyond premiums, your HSA still covers the wide range of other qualified medical costs it always has, such as deductibles, copays, dental, and vision. So even after contributions stop, the account keeps doing real work in retirement.
An HSA can quietly help with IRMAA, but the help comes from the contribution side, not the spending side. While you are still eligible to contribute, every dollar you put in lowers your adjusted gross income for that year. Since your MAGI for IRMAA is built on your AGI, a lower AGI means a lower MAGI.
That can matter more than it looks. IRMAA works on hard thresholds, and going even slightly over one can lift your Medicare premiums two years later. Trimming your MAGI with an HSA contribution in the years that count can be enough to keep you under a bracket and avoid the IRMAA cliff. To see exactly which income flows into the number, read what counts as MAGI.
The timing point is worth repeating. The IRMAA benefit only comes from contributions made while you were still eligible, which means before Medicare starts. Once you are on Medicare and contributions stop, the HSA no longer lowers your MAGI, though it still pays bills tax-free.
Source: IRS HSA rules (Publication 969) and Medicare guidance. Informational only, not tax or medical advice. Last verified June 2026.