HSA vs FSA Calculator

Quick answer: HSA or FSA?

If you're enrolled in a high-deductible health plan (HDHP), an HSA is usually the better account: the money is yours to keep, rolls over every year, can be invested, and comes out tax-free for medical costs. A health FSA works with almost any employer plan, but it's mostly "use it or lose it", so only put in what you're sure to spend. Through payroll, both save federal income tax and the 7.65% Social Security and Medicare tax — for a single filer earning $75,000 in Texas, about 30 cents on every dollar.

You generally can't have both a regular health FSA and an HSA, but you can pair an HSA with a limited-purpose FSA for dental and vision (IRS Publication 969).

HSA vs FSA side by side (2026 and 2027)

2026 HSA limits: Rev. Proc. 2025-19. 2027 HSA limits: Rev. Proc. 2026-24. 2026 FSA limit and carryover: IR-2025-103. The 2027 FSA figures are an estimate until the IRS publishes them.

How much tax you actually save

Your saving per dollar is your federal tax bracket, plus 7.65% for Social Security and Medicare (through payroll), plus your state rate. These rows come from the calculator, single filer, 2026 tax rules:

An HSA contribution you make outside payroll is still deductible from income tax, but it doesn't avoid Social Security and Medicare tax — so payroll is worth about 7.65 cents more per dollar. If you're over the Social Security wage base, only Medicare applies.

California and New Jersey tax HSA contributions

Most states follow the federal rules, but California and New Jersey don't treat HSAs as tax-favored: payroll HSA contributions are added back to state wages, and earnings are taxed each year (Clarity Benefit Solutions). Both states do exclude health FSA contributions. On a $75,000 salary in California, $3,400 into an HSA saves $1,052, while $3,400 into an FSA would save $1,324 (if you spend it). The calculator applies this automatically. Most HSA calculators we looked at ignore state rules or ask you for a flat rate.

How much to put in an FSA (and what you could lose)

The right FSA election is the amount you're sure to spend, plus the carryover if your plan has one. Every dollar above that is a bet. Example: $75,000 salary in Texas, $2,000 of predictable costs (prescriptions, copays, a dentist visit).

With a carryover, $2,680 is the "safe" amount — the extra $680 rolls into next year. Without a carryover, every unspent dollar over $2,000 costs you about 70 cents, after the tax you saved on it. A plan can offer a carryover or a grace period of up to 2½ months, but not both (Publication 969).

What changed for HSAs in 2026

The 2025 tax law (Pub. L. 119-21) widened who can use an HSA, starting in 2026 (IRS; Notice 2026-5):

• Bronze and catastrophic Marketplace plans count as HSA-eligible from 2026, even when their deductibles don't meet the usual HDHP test. Buying the same plan off the exchange also counts; small-business (SHOP) coverage generally doesn't.
• Direct primary care memberships no longer block HSA eligibility if the fee is up to $150 a month ($300 for more than one person), and you can pay those fees from your HSA.
• Telehealth before the deductible no longer blocks eligibility — permanently, and retroactive to 2025.

A court in July 2026 paused part of a separate 2027 Marketplace rule that would have expanded who can buy catastrophic plans; that doesn't change the IRS rule that catastrophic plans count as HDHPs. None of the HSA calculators we reviewed covered these changes.

HSA eligibility traps: FSAs, Medicare and the last-month rule

• A general-purpose FSA blocks HSA contributions, including a spouse's FSA that covers you. A grace period can block the first months of the next year unless your FSA balance is $0 at year end (Publication 969).
• Medicare ends HSA eligibility for the months you're enrolled. If you sign up after 65, Part A is usually backdated up to six months, so stop HSA contributions six months before you apply to avoid an excess contribution.
• The last-month rule: if you're HSA-eligible on December 1, you can contribute the full year's limit, but you must stay eligible through December 31 of the next year. If you don't, the extra is taxed and hit with a 10% additional tax.

Dependent care FSA: $7,500 from 2026

Separate from health accounts, a dependent care FSA for child care or adult day care rose to $7,500 per household from 2026 ($3,750 if married filing separately), up from $5,000 (26 U.S.C. § 129; Hill Ward Henderson). It isn't indexed for inflation. Dollars you run through it can't also be used for the child and dependent care credit.

Open enrollment and year-end deadlines

Buying your own coverage? The enhanced premium tax credits that ran through 2025 had not been extended by Congress as of our last check, and the IRS's 2027 table uses the pre-2021 rules, with no credit above 400% of the poverty line (Rev. Proc. 2026-26). Check your actual price on HealthCare.gov or your state exchange.

Common questions

Can I have an HSA and an FSA at the same time?

Only a limited-purpose FSA (dental and vision) or a post-deductible FSA. A regular health FSA — yours or a spouse's that covers you — makes you ineligible to contribute to an HSA.

Does employer money count toward my HSA limit?

Yes. Employer HSA contributions count toward the same limit, so enter them in the calculator. Employer FSA money doesn't count toward your FSA salary-reduction limit.

What happens to my FSA if I leave my job?

Usually you lose any unspent balance (you may be offered COBRA for the FSA). Many plans let you spend the full year's election early, which can work in your favor.

Can I change my HSA contribution mid-year?

Yes, HSA payroll contributions can usually be changed at any time. FSA elections are fixed for the year unless you have a qualifying life event.

Is it worth funding an HSA if I'm healthy?

Often, yes: the money rolls over, can be invested, and can be used for medical costs in retirement. After 65 you can also withdraw it for anything, paying only income tax, like a traditional IRA.

Sources

1. Rev. Proc. 2025-19: 2026 HSA and HDHP amounts — Internal Revenue Service. Accessed October 14, 2026.
2. Rev. Proc. 2026-24: 2027 HSA and HDHP amounts — Internal Revenue Service. Accessed October 14, 2026.
3. IRS releases tax inflation adjustments for tax year 2026 (IR-2025-103; Rev. Proc. 2025-32) — Internal Revenue Service. Accessed October 14, 2026.
4. Publication 969: Health Savings Accounts and Other Tax-Favored Health Plans — Internal Revenue Service. Accessed October 14, 2026.
5. Treasury, IRS provide guidance on new tax benefits for health savings account participants (IR-2025-119; Notice 2026-5) — Internal Revenue Service. Accessed October 14, 2026.
6. Notice 2026-5: HSA changes under Pub. L. 119-21 — Internal Revenue Service. Accessed October 14, 2026.
7. Not every state treats HSAs the same: 2026 compliance roadmap for multi-state employers — Clarity Benefit Solutions. Accessed October 14, 2026. Secondary source (August 18, 2026).
8. 26 U.S. Code § 129 (dependent care assistance programs) — Legal Information Institute, Cornell Law School. Accessed October 14, 2026.
9. Dependent care FSA limit increased to $7,500 for 2026 — Hill Ward Henderson. Accessed October 14, 2026. Secondary source.
10. 2027 Medicare Advantage & Part D landscape: state-by-state fact sheets — Centers for Medicare & Medicaid Services. Accessed October 14, 2026.
11. Dates and deadlines for 2027 health insurance — HealthCare.gov. Accessed October 14, 2026.
12. Rev. Proc. 2026-26: 2027 premium tax credit applicable percentages — Internal Revenue Service. Accessed October 14, 2026.

Research checked October 14, 2026.