HSA Contribution Limits with Mid-Year Medicare Enrollment

When a taxpayer enrolls in Medicare, their HSA contribution limit becomes zero beginning with the first month of Medicare enrollment [1]. For someone who signs up for Medicare in April 2025, they can only contribute for the months they were eligible before Medicare enrollment.

Calculation:

The taxpayer would be eligible for January, February, and March 2025 (3 months). Using the monthly calculation method, you would take the annual family coverage limit and prorate it [1].

For 2025, the family coverage limit is $8,550 (under age 55) or $9,550 (age 55 or older) [3].

The prorated contribution would be:

• Under age 55: ($8,550 / 12) x 3 months = $2,137.50
• Age 55 or older: ($9,550 / 12) x 3 months = $2,387.50

The exact amount depends on whether the taxpayer is age 55 or older during 2025.