Your contribution is only what you can deduct. Medicare coverage does not work with HSA eligibility, but it is personal coverage. Because HSA accounts are individual trust accounts, if one spouse is insured by Medicare, the other spouse's eligibility to contribute to an HSA account.
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HSA Eligibility for Spouses of Medicare Enrollees
Because HSA eligibility is determined at the individual
level, an individual’s enrollment in Medicare would not
affect his or her spouse’s eligibility to establish and
contribute funds to his or her spouse’s HSA, even if both
spouses are enrolled in the same non-Medicare plan. For
example, Spouse 1 and Spouse 2 are enrolled in an HSA
eligible HDHP (family coverage) through Spouse 1’s
employer. Spouse 1 is also enrolled in Medicare. Assuming
Spouse 2 is otherwise eligible, Spouse 2 may establish and
contribute to his or her own HSA, which may be outside of
Spouse 1’s employment setting. Spouse 1 may not make
contributions to his or her own account on behalf of Spouse
2.
As with contribution limits generally, the maximum amount
that Spouse 2 can contribute to his or her own HSA is tied
to the type of coverage Spouse 2 was enrolled in during the
tax year (in this instance, family coverage); Spouse 2’s age;
and the months that Spouse 2 was considered eligible.
Spouse 1’s lack of eligibility to contribute to his or her
HSA would not affect the maximum HSA contribution
amount available to Spouse 2, other than the fact that the
couple no longer needs to determine how to split the
maximum contribution amount between the spouses’ HSA
