HSA vs. FSA Calculator
Work out which account saves you more in 2026, and how much you can actually put in.
Health savings accounts and flexible spending accounts both cut your tax bill, but they behave very differently: HSA money is yours forever and can be invested, while FSA money largely disappears at year end. The right choice depends on your coverage, your age, and how much you actually expect to spend.
Set your details below to see your maximum 2026 HSA contribution ($4,400 self-only, $8,750 family, before any employer money), a right-sized FSA election, and the estimated federal tax savings from each.
Before you start: this calculator assumes you’re enrolled in an HSA-qualified high-deductible health plan (HDHP). If you’re not, you can’t contribute to an HSA at all and only the FSA column applies.
$1,305
on $4,400 contributed
$795
on $2,680 elected
The HSA is the stronger option here, saving about $510 more than the FSA election. It also carries no use-it-or-lose-it deadline: unused HSA money rolls over indefinitely and can be invested. If you contribute to an HSA, you generally cannot also fund a full-purpose health FSA in the same period.
Unused HSA funds roll over forever and can be invested.
No forfeiture risk at this election, assuming you spend $2,000. Up to $680 may carry over.
- You generally cannot contribute to both an HSA and a full-purpose health FSA in the same period; a limited-purpose FSA (dental and vision only) is the usual exception and isn’t modeled here.
- Savings shown are federal only. California and New Jersey do not exempt HSA contributions from state income tax.
Common questions
Can I have both an HSA and an FSA?
Not in the usual sense. Being covered by a full-purpose health FSA, including through a spouse’s plan, disqualifies you from contributing to an HSA for that period. The common exception is a limited-purpose FSA, which covers dental and vision only and can sit alongside an HSA.
What happens to my HSA when I go on Medicare?
Enrolling in any part of Medicare, including premium-free Part A, ends your ability to make new HSA contributions. Your existing balance stays yours and can still be spent tax-free on qualified expenses, including Medicare premiums. Because Part A can start retroactively by up to six months for people enrolling after 65, it is common guidance to stop contributing roughly six months before you file.
How much should I put in an FSA?
Elect close to what you genuinely expect to spend. The $680 carryover cushion means a modest overshoot is recoverable, but anything above your expected spend plus that carryover is forfeited at year end. The calculator flags that risk as you move the slider.
Not medical, tax, or financial advice: this calculator is for general educational purposes only. It uses federal figures for the 2026 tax year, ignores state taxes, and cannot account for your full circumstances. Confirm contribution limits and eligibility with the IRS, your plan administrator, or a qualified tax professional before you act.