HSA contribution after going on Medicare

[Otz]

I was enrolled in a family HDHP from Jan 1st through April 30th of 2024.  During that time I did not make any HSA contributions.  On May 1, 2024 I went on Medicare.  Can I still make a HSA contribution for 1/1/2024 through 4/30/2024 before the April 15th 2025 deadline?

[NCperson]

yes - Assuming you turned 65 in May, 2024 you can contribute 3/12's of the annual limit no later than April 15, 2025. 

However, if you turned 65 prior to May, you have to stop contributing to your HSA six months prior to May ,but no further back than the month prior to turning 65.

[BillM223]

It depends on when you turned (or will turn) 65. If you qualify (see below), you have just a few days to do it (before April 15th).

You MUST tell the HSA custodian that the contribution is for 2024, or else they will mark it for 2025.

Note that despite the language of the IRS and many websites that suggests that you cannot contribute to an HSA once you are on Medicare, in fact, the annual HSA contribution limit is calculated on an annual basis, and the contributions are not dated. 

So if there was no Medicare coverage from January through April, you can contribute one-third of $8,300 (plus one-third of $1,000 since you are presumably 55+)...as I said, before April 15th.

As for the 6-month look back, it depends on when you turn 65. If you start Medicare before you turn 65, there is no lookback. The lookback happens only when you start Medicare after you turn 65, in which case, the lookback is from the date you start Medicare back to your 65th birthday, but the lookback is never more than 6 months.

"You can sign up for Part A any time after you turn 65. Your Part A coverage starts 6 months back fro...."

So if you signed up for Medicare in your 65th birthday (May), then there is no lookback, so there would be no conflicting coverage for an HDHP or to contributing to an HSA in the months prior.

[Edited 4/10/2025 | 7:55 PST]

[NCperson]

@BillM223 - sorry but this is NOT accurate...it has nothing to do with the FRA; it has to do with the applicant's age at application.  FRA is a Social Security concept and has nothing to do with Medicare.  

Eligibility to contribute to the HSA ends six months prior to the month you are enrolled in Medicare, but no further back than the month prior to turning 65 years old.   

here is one article that discussed the lookback.  

https://www.journalofaccountancy.com/issues/2021/jul/medicare-rules-on-hsa-after-age-65/

• There is a six-month lookback period (but not before the month of reaching age 65) when enrolling in Medicare after age 65, so a best practice is for workers to stop contributing to their HSA six months before the month they apply for Medicare to avoid penalties. Note that the month of application is what is used to calculate the six-month lookback, not the month the applicant wishes to begin benefits. See the examples below for more on this.

[BillM223]

@NCperson 

Thank you for catching that - I was thinking of something else. I have edited my answer. I was happy to clarify for the user the if he/she turned 65 in May (hence the application for Medicare), then he/she would be able to contribute to the HSA using the HSA contribution limit for 4 months.

[Otz]

Thank you for your help.  Just what I needed.