How is a contribution limit determined for each spouse if one or both spouses have an HDHP with family coverage?

If both spouses are eligible individuals, the total contribution limit for both spouses cannot exceed the family coverage maximum contribution, divided equally between the spouses unless they agree upon a different division. Regardless of how the limit is divided between the spouses, the aggregate contributions between the two spouses cannot exceed the maximum annual contribution amount for family coverage, (i.e., $6,900 for 2018).

EXAMPLE: Leah and Jon are married. They are both 42 years old and both have family coverage under HDHPs. In this scenario, Leah and Jon in aggregate cannot exceed a contribution of $6,900 for 2018. Each may contribute $3,450 to an HSA for 2018, unless they decide to divide the amount in a different way.

Catch-up contributions: One or both spouses may make catch-up contributions, if age eligible. For example, if both spouses are age 55 or older by the end of 2018, total contributions to their HSAs cannot exceed $8,900 ($6,900 maximum limit + $1000 catch-up for each spouse), when both have family coverage.

Archer MSA contributions: The family coverage limit is reduced by any contributions to Archer MSAs.