Transparent calculator methodology
Build HSA contribution room one month and one spouse at a time
HSA contribution room can change when either spouse changes HDHP tiers, receives general-purpose FSA or HRA coverage, enrolls in Medicare, or qualifies for an age-55 catch-up. Employer deposits use the same annual room.
What the estimate includes
- Monthly self-only, family, or no-HDHP coverage for two spouses
- General-purpose FSA, HRA, and other disqualifying coverage start and end windows
- Employer and employee contributions, dependent status, and separate age-55 catch-ups
- Prorated limit, last-month-rule alternative, and Medicare Part A stop-date estimate
How the comparison works
Eligibility is tested on the first day of each month after applying coverage windows, dependent status, and Medicare enrollment. The calculator applies the 2026 self-only or shared family basic limit once per household, allocates family room between spouses, adds separate eligible catch-ups, and compares employer plus employee deposits with both the prorated and last-month-rule amounts.
Important limitation
This is a planning estimate, not an eligibility or filing determination. Confirm the exact coverage design, FSA or HRA reach, Medicare Part A effective date, spousal allocation, testing period, correction process, and state treatment with the plan administrator, Medicare or Social Security notice, and a qualified tax professional.