HSA vs FSA Calculator (2026)
Compare 2026 HSA and FSA rules side by side. Enter your coverage, expected medical expenses, and tax rate to see each account's limit, your suggested contribution, and the estimated tax savings.
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HSA vs FSA: the 60-second version
Both accounts let you pay medical bills with pre-tax dollars, but they behave very differently after that. An HSA is a long-term account you own: money rolls over forever, can be invested, and follows you between jobs — but you must be enrolled in a high-deductible health plan (HDHP) to contribute. A health FSA is available through most employer plans with no HDHP requirement, but it's use-it-or-lose-it: spend it this year or forfeit it (your employer may let up to $680 carry over into 2026's plan year).
2026 limits at a glance
| Account | 2026 limit | Notes |
|---|---|---|
| HSA, self-only | $4,400 | Requires HDHP enrollment |
| HSA, family | $8,750 | Requires HDHP enrollment |
| HSA catch-up (55+) | +$1,000 | Account holder's age, per person |
| Health FSA | $3,400 | Employer plan required |
| FSA carryover | up to $680 | Only if your employer offers it |
Worked example
Self-only coverage, HDHP enrolled, $3,000 in expected medical expenses, 22% marginal rate:
| Step | HSA | FSA |
|---|---|---|
| 2026 limit | $4,400 | $3,400 |
| Suggested contribution | min($3,000, $4,400) = $3,000 | min($3,000, $3,400) = $3,000 |
| Est. income-tax savings | $3,000 × 22% = $660 | $3,000 × 22% = $660 |
| Unspent money | Rolls over | Forfeited (up to $680 carryover) |
Same dollars, same immediate tax savings — the difference is what happens to anything you don't spend, and whether you can keep contributing year after year. With $6,000 in expenses, the HSA pulls ahead on capacity: $4,400 vs $3,400, leaving $1,600 less to pay out of pocket.
Choosing between them
- Pick the HSA if you have an HDHP and can afford to contribute more than you'll spend — the rollover and investing make it a retirement-style account, not just a spending account.
- Pick the FSA if you don't have an HDHP, or your expenses are predictable and fit under $3,400 — but elect conservatively if your plan has no carryover.
- Don't fund both a general-purpose FSA and an HSA in the same year — the FSA disqualifies the HSA (a limited-purpose dental/vision FSA is the exception).
Data sources: IRS Revenue Procedure 2025-19 (HSA limits) and 2025-32 (FSA limit and carryover), 2026 plan year. This page is an information comparison, not tax or investment advice — "estimates only, not tax advice."
Frequently asked questions
Do I need a high-deductible health plan (HDHP) for an HSA?
Yes — HSA eligibility requires enrollment in a qualifying HDHP, and you can't have other disqualifying coverage. A general-purpose health FSA counts as disqualifying coverage, which is why you generally can't hold both at once. The one common exception is a limited-purpose FSA restricted to dental and vision expenses, which is allowed alongside an HSA.
What happens to money I don't spend in each account?
This is the biggest practical difference. HSA balances roll over year after year with no deadline, and you can invest them — the money is yours even if you change jobs. Health FSA money is use-it-or-lose-it: unspent funds are forfeited at year-end unless your employer offers the IRS-allowed carryover (up to $680 for 2026) or a grace period.
Why is the HSA called triple tax-advantaged?
Contributions are pre-tax (or deductible), growth inside the account is tax-free, and withdrawals for qualified medical expenses are tax-free. After age 65, you can also withdraw for non-medical reasons — you just pay ordinary income tax, like a traditional IRA. No FSA offers that combination.
What counts as a qualified medical expense?
The IRS Publication 502 list: copays and deductibles, prescriptions, dental work, vision care, glasses, mental-health visits, and many over-the-counter items. Cosmetic procedures and general health-club dues generally don't qualify. Both HSAs and FSAs use the same qualified-expense list.
Can I contribute to both an HSA and an FSA?
Not a general-purpose health FSA — that disqualifies you from HSA contributions. A limited-purpose FSA (dental and vision only) or a dependent-care FSA can coexist with an HSA. If your employer offers a general FSA and you want the HSA, you typically must decline the FSA.
How does this calculator do the math?
It caps your suggested HSA contribution at the 2026 limit for your coverage ($4,400 self-only, $8,750 family, plus $1,000 if you're 55+), and your FSA contribution at $3,400. Estimated tax savings are the contribution times your marginal rate — a simple, comparable figure for both accounts. It doesn't model FICA savings through payroll (both accounts qualify) or investment growth.
Estimates only, not tax or financial advice. Figures reflect the 2026 tax year. Verify important decisions with the IRS or a qualified tax professional.