How do contributions work if both spouses have individual HSAs?

If each is enrolled in their own plan as self-only coverage, the maximum amount that can be contributed to each account is limited to the individual IRS contribution limit. If either spouse has family HDHP coverage, both spouses are treated as having family HDHP coverage, and the contribution limit is combined for both spouses and limited to the family IRS contribution limit. The contribution limit is split equally between the spouses unless there is an agreement on a different division. If each spouse has family coverage under a separate plan, the contribution limit is combined for both spouses and limited to the family IRS contribution limit. The contribution limit is split equally between the spouses unless there is an agreement on a different division.