| Medicare starts | Months eligible | Regular limit | With catch-up |
|---|---|---|---|
| March 1 | 2 | $750 | $917 |
| May 1 | 4 | $1,500 | $1,833 |
| July 1 | 6 | $2,250 | $2,750 |
| September 1 | 8 | $3,000 | $3,667 |
| November 1 | 10 | $3,750 | $4,583 |
Months eligible = months before the month Medicare coverage starts. A month counts if you are eligible on its first day.
Details that surprise people
- Any Medicare enrollment counts, including premium-free Part A. Enrolling in Part A or B ends eligibility to contribute from the first month of coverage.
- Part A can be retroactive. If you apply for Medicare or Social Security after 65, Part A coverage can start up to six months back, so contributions made in that window can become excess contributions. Stop contributing about six months before you plan to apply.
- You can still spend your existing HSA balance tax-free on qualified medical costs, including Medicare premiums (not Medigap).
- Staying on an employer HDHP past 65 and delaying Medicare is how some people keep contributing; that is a decision for an advisor or the SSA.
Worked example
A 65-year-old has self-only HDHP coverage and Medicare Part B starts August 1, 2027. Months eligible: 7. Limit: $4,500 × 7 ÷ 12 = $2,625, plus catch-up $1,000 × 7 ÷ 12 = $583, for a total of $3,208. If their employer deposits $1,200, they have $2,008 of room.
Sources: IRS Publication 969; Medicare.gov. Checked October 18, 2026.
Related: HSA at 55 · HSA vs PPO near retirement · 2027 limits hub.
This is general information, not tax or insurance advice. Confirm details with your plan documents, the IRS and a qualified professional.
General education, not insurance, tax or legal advice. Figures from IRS and HHS publications; confirm with your plan documents.