An HSA can combine federal tax benefits with long-term invested assets, but contribution eligibility, deductible funding and qualified withdrawals are separate questions. This calculator starts with one owner’s selected-year contribution room and tax estimate, then compares two ways to pay medical bills using the same household cash budget. It supports dated 2025 and 2026 contribution rules and a hypothetical future funding plan; it does not establish personal eligibility or recommend an account for every household.
How the HSA Calculator works
The contribution model reuses dated federal eligibility and limit helpers. First-day monthly facts, age on December 31, other coverage, Medicare and direct primary care assumptions determine the modeled cap. Employer deposits consume the same room as personal deposits. Unknown facts remain unresolved; existing account assets can still be projected when no new deposits are requested.
Only modeled allowable personal deposits receive the entered federal and state deduction estimate. Payroll funding also uses wage-dependent Social Security, Medicare and employer Additional Medicare withholding components. Direct contributions receive no modeled payroll reduction, and state conformity must be verified separately.
Read requested amounts and modeled amounts together: an over-limit request is not treated as an allowable deposit, and employer funding does not create a second personal deduction. A zero result can have different causes from unresolved eligibility, so inspect the current-year table before comparing projections. Change only the assumptions you can verify, and use the detailed planner when the simple monthly checklist does not describe your situation.
Inputs and what they mean
The growth ledger applies each year’s signed investment change before end-of-year deposits and qualified medical withdrawals. It shows funding, investment change, withdrawals and remaining HSA assets together. Future deposits repeat the selected-year modeled amount only for the chosen number of funding years; future eligibility and limits are not predicted.
Both payment paths use the same personal-deposit and medical cash budget. When the HSA pays qualified bills, the released cash goes to a matched outside account at the entered after-tax return. Compare combined assets as well as the HSA balance. Nominal and starting-year-dollar views use the same underlying ledger; lower or negative returns remain possible.
Year zero is the entered starting balance before future deposits. Changing the years of deposits affects projected funding rather than certifying future contribution room. Starting-year-dollar amounts use each plotted year’s inflation scale, while the current contribution cap and entered annual bills remain nominal. Use the visible ledger to check a selected chart year; hiding a plotted series does not remove its amount from the canonical report or alter the underlying financial calculation.
Limits and edge cases
The optional last-month comparison keeps its ordinary monthly cap and conditional uplift separate. The testing period extends through the following December 31; a resolved failure can cause income inclusion and an additional 10% tax, subject to applicable exceptions. Future or unknown testing facts do not become a settled tax liability.
For 2026, qualifying individual bronze and catastrophic plans and qualifying direct primary care arrangements have distinct rules. A fee above the DPC contribution-eligibility cap can still be a separately qualified expense reimbursable from an existing HSA; employer-paid fees cannot be reimbursed again. This tool does not decide medical qualification, corrective distributions, spouse allocation, state taxation or complex retroactive Medicare dates. Use the detailed eligibility planner for date and couple scenarios, and verify primary IRS sources before acting.
Review the selected-year assumptions before exporting or sharing. Browser storage and a value-bearing link are different disclosures; keeping an old saved record does not verify its intended amounts or eligibility. The report preserves entered and active assumptions so inactive drafts are not mistaken for calculated facts.