When to stop HSA contributions before Medicare
Estimate the last HSA-eligible month when premium-free Medicare Part A may begin retroactively.
Medicare advises people applying for premium-free Part A after age 65 to stop HSA contributions at least six months before applying. Part A can begin up to six months retroactively, but not before the first month of Medicare eligibility.
Why enrollment can create an excess contribution
HSA eligibility ends with the first month of Medicare coverage. When premium-free Part A is backdated, a contribution that appeared valid when deposited may fall in a month that later becomes Medicare-covered. That contribution can become excess even if the account owner had an HSA-qualified plan at the time.
Use both dates
The six-month warning is capped by the first month the person could be covered by Medicare. Someone applying shortly after turning 65 cannot be backdated to a month before Medicare eligibility. The calculator therefore asks for both the application month and the first eligible month.
Do not confuse enrollment and contributions
You may keep and spend an existing HSA after Medicare starts. The restriction is on new contributions. Qualified medical distributions remain tax-free, and Medicare premiums can be qualified expenses in specified circumstances.
People retiring before Medicare may use Marketplace coverage during the gap. In that period, deductible HSA contributions can affect ACA MAGI when all HSA eligibility rules are met. Model that separate income cliff with the ACAIndex subsidy calculator.