My spouse will enroll in Medicare this year and our HDHP coverage will change from family to single. How do I prorate my HSA contributions to account for that?

My spouse will enroll in Medicare this year and our HDHP coverage will change from family to single. How do I prorate my HSA contributions to account for that?: Changing from family HDHP coverage to single will impact the amount you may contribute. You may contribute 1/12 of your family contribution (including any catch up contribution) for each month you have family HDHP coverage + 1/12 of the single contribution (including any catch up contribution) for each month you have single coverage based on your status on the first of the month.