Personal finance · free calculator
HSA vs FSA tax savings calculator
Compare HSA and FSA tax savings, including HSA's triple-tax-free compounding for retirement-bucket use.
Limits
2026 HSA and FSA inputs
Tax setup
Current-year tax rates and funding
HSA long game
Future value of unused HSA dollars
HSA current-year tax saved
Includes federal, state, and FICA savings
FSA current-year tax saved
Assumes salary-reduction FSA payroll treatment
Unused HSA future value
$1,600 left unspent grows to this value
FSA forfeiture risk
$680 protected by carryover, if any
HSA net edge
HSA leads because unused FSA dollars would be forfeited, while unused HSA dollars keep compounding tax-free.
HSA scenario
2026 HSA math
- Allowed contribution$3,400
- Current-year tax savings$1,178
- After-tax cost of this year's medical spend$1,176
- Unused amount left to invest$1,600
- Tax-free growth on unused amount$4,591
- Total HSA economic benefit$5,770
FSA scenario
2026 FSA math
- Allowed contribution$3,400
- Current-year tax savings$1,178
- After-tax cost of this year's medical spend$1,176
- Unused amount$1,600
- Carryover preserved$680
- Forfeited amount$920
- Total FSA economic benefit$258
Important eligibility note
This comparison assumes you are otherwise HSA-eligible. A general-purpose health FSA usually blocks HSA contributions for the same coverage period. If your employer offers a limited-purpose or post-deductible FSA, the coexistence rules can be different.
HSA vs FSA: same front-end tax break, different long-run math
Both accounts let you pay qualified medical expenses with pre-tax dollars. That means the immediate tax savings can look very similar on the surface. The real difference shows up after the current plan year ends.
A health savings account (HSA) is portable, rolls forward forever, and can be invested. A health flexible spending arrangement (FSA)is usually stronger only when you are confident you will use nearly every dollar this year. If you over-elect into an FSA, the forfeiture risk can erase part of the tax win.
The HSA advantage: tax break in, tax-free growth, tax-free medical use out
- Contributions are tax-favored up front.
- Investment growth stays untaxed inside the HSA.
- Qualified medical withdrawals stay tax-free.
That makes the HSA one of the few accounts in the tax code with truly triple-tax-free treatment. If you can cash-flow current medical bills and leave the HSA invested, the long-run value compounds far beyond an FSA election.
Where an FSA still makes sense
FSAs are often best for predictable near-term expenses: orthodontics, recurring therapy, known surgery years, prescriptions, or a family with steady annual out-of-pocket costs. In those cases, the payroll-tax savings are real and the expiration risk stays low.
Payroll HSA vs direct HSA matters
Direct HSA contributions still create a tax deduction, but payroll HSA contributions are typically better because they also avoid Social Security and Medicare tax. This calculator separates those two routes so you can see when the FSA wins the current-year comparison purely because of payroll-tax treatment.
2026 IRS limits used here
- HSA self-only limit: $4,400
- HSA family limit: $8,750
- HSA age-55 catch-up: $1,000
- Health FSA salary-reduction limit: $3,400
- Maximum health FSA carryover, if the plan allows it: $680
The eligibility caveat most people miss
A general-purpose health FSA usually makes you ineligible to contribute to an HSA for the same coverage period. The common workaround is a limited-purpose or post-deductible FSA. If your benefits menu includes those variants, the coexistence rules change and you should verify the exact plan design before contributing.
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