HSA vs FSA savings calculator
On a $3,000 payroll contribution at a 22% marginal federal rate, an HSA and an FSA save you the exact same $889.50 in tax this year (about $660.00 in income tax plus $229.50 in payroll tax). The tax math is identical because both are pre-tax payroll deductions. What differs is what happens to money you don't spend: an HSA (2026 cap $4,400 self-only / $8,750 family) rolls over forever and can be invested, while an FSA (2026 cap $3,400) is largely use-it-or-lose-it. Enter your own numbers below.
How much will an HSA or FSA actually save me?
Both a health savings account (HSA) and a flexible spending account (FSA) let you set aside money before it's taxed. The savings come from two places: the income tax you don't pay on the contribution, and, if the money comes out of your paycheck, the 7.65% payroll (FICA) tax for Social Security and Medicare that you also skip. Add your federal marginal rate, any state rate, and 7.65% if it's payroll, and you get your total percentage saved on every dollar contributed, up to that account's cap.
The calculator below runs that math for both accounts side by side, using the verified 2026 IRS limits, so you can see your actual dollar savings and whether your planned contribution fits under either cap.
Calculate your HSA vs FSA savings
The table starts filled in with a $3,000 contribution, 22% marginal federal rate, payroll deduction, and family HDHP coverage. Change any field to see your own numbers.
leave at 0 if your state doesn't tax the contribution, or if you're not sure
money your employer puts in counts against the same cap, before your own contribution
| Result | HSA | FSA |
|---|---|---|
| 2026 contribution cap | $8,750.00 | $3,400.00 |
| Amount that fits under the cap | $3,000.00 | $3,000.00 |
| Federal + state income tax saved | $660.00 | $660.00 |
| Payroll (FICA) tax saved | $229.50 | $229.50 |
| Total tax savings | $889.50 | $889.50 |
| What happens to money you don't spend | Stays yours, rolls over every year, can be invested | Forfeited at year end, unless a small carryover or grace period applies |
For this contribution, the HSA and FSA save you the same $889.50 in tax. Since the amounts tie, the decision comes down to risk: the HSA lets this money sit and grow for years if you do not spend it, while the FSA needs to be spent down by the plan year deadline (plus any carryover or grace period) or it is forfeited.
2026 caps: IRS Revenue Procedure 2025-19 (HSA) and Revenue Procedure 2025-32 (FSA). Tax savings are calculated from the rate and payroll status you enter; they are illustrative math, not tax advice, and your actual refund or withholding change depends on your full return.
Why do an HSA and an FSA save the same amount in taxes?
Both accounts work through the same mechanism: money is deducted from your pay before federal income tax, state income tax (in most states), and FICA payroll tax are calculated, then it's set aside for medical costs. Since the deduction happens the same way for the same dollar amount, the tax saved on that dollar is identical whether it lands in an HSA or an FSA. A $3,000 contribution at a 22% marginal rate through payroll saves the same $889.50 either way. The accounts only diverge in what happens next: an HSA contribution becomes yours permanently, while an FSA contribution is spent down on a clock set by your employer's plan year.
What's the catch with an FSA?
The catch is the deadline. A health FSA is "use it or lose it": money you don't spend on qualified medical expenses by the end of the plan year is forfeited back to the plan, not refunded to you. Many employers soften this with one of two features, never both at once: a carryover of up to $680 into the next year, or a grace period of about two and a half extra months to spend the full remaining balance. Neither is guaranteed; some plans offer neither, in which case the year-end cutoff is absolute. See FSA contribution limits for 2026 for the full carryover and grace-period rules.
What's the triple tax advantage that only the HSA has?
An HSA is the only account IRS Publication 969 gives all three tax breaks to at once: contributions go in pre-tax, the balance grows tax-free while it's invested, and withdrawals for qualified medical expenses come out tax-free. An FSA only gets the first of the three. It also has no HDHP requirement, but it forgoes the tax-free growth and tax-free-withdrawal legs entirely because the money can't be invested and doesn't stick around long enough to compound.
What are the 2026 HSA and FSA contribution limits?
| Account | 2026 limit |
|---|---|
| HSA, self-only HDHP coverage | $4,400 |
| HSA, family HDHP coverage | $8,750 |
| HSA catch-up, age 55+ | +$1,000 (on top of either HSA limit) |
| Health FSA | $3,400 |
| Health FSA carryover (if the employer offers it) | up to $680 |
Source: IRS Revenue Procedure 2025-19 (HSA/HDHP) and Revenue Procedure 2025-32 (FSA). See HSA contribution limits for 2026 and FSA contribution limits for 2026 for the full breakdown, including HDHP eligibility thresholds and the dependent care FSA.
Note that the HSA limit depends on your HDHP coverage tier (self-only or family), while the FSA limit is a flat per-employee figure that doesn't change with coverage type. That's why the calculator above only asks for coverage type on the HSA side.
Does my state tax HSA contributions?
Usually not, but not always, which is why the calculator has a separate state-rate field. Most states follow the federal rule and don't tax HSA contributions or growth. California is a documented exception: the state Franchise Tax Board does not conform to the federal HSA rules, so HSA contributions are not deductible on a California return and HSA earnings are taxed as they're earned, year by year. If you live somewhere that doesn't recognize the HSA's state tax break, set the state-rate field to 0 for the HSA column's real-world answer, even if you'd enter a nonzero state rate for an FSA (which most states do treat as pre-tax). Check your own state's tax agency before assuming either way.
When does the FSA make more sense?
Pick the FSA when you don't have a qualifying HDHP (so an HSA isn't even an option) or when you have a traditional, lower-deductible health plan and know roughly what you'll spend on care in the coming year, such as ongoing prescriptions, contacts, or a planned procedure. Because you're confident you'll spend most of the election, the use-it-or-lose-it risk is small and you still capture the same pre-tax savings.
When does the HSA make more sense?
Pick the HSA whenever you're enrolled in a qualifying HDHP and can afford to pay near-term medical costs out of pocket or from other savings, leaving the HSA balance to roll over and, once it clears your provider's investment threshold, grow invested for years. Because the money never expires and follows you between jobs, many people treat a well-funded HSA as a second retirement account earmarked for future medical costs. See HSA vs FSA: what's the difference? for the full ownership and portability comparison, including whether you can pair an HSA with a limited-purpose FSA.
Worked example: maxing out a family HSA vs the FSA cap
Say a family is HDHP-eligible, contributes through payroll, and sits in a 22% federal bracket with no state HSA tax.
- FSA path. They contribute the full $3,400 FSA cap. Tax saved: $3,400 × (22% + 7.65%) = about $1,010.10. If they spend $3,000 of it and their plan has no carryover or grace period, the remaining $400 is forfeited on December 31.
- HSA path. They contribute the full $8,750 family HSA cap instead. Tax saved: $8,750 × (22% + 7.65%) = about $2,601.88, more than twice the FSA's savings simply because the cap is more than twice as large. Whatever they don't spend stays in the account, available next year and every year after.
The lesson isn't that the HSA is "worth more" dollar for dollar (the tax rate on each dollar is the same); it's that the HSA lets you shelter far more of your medical spending from tax in the first place, with none of the year-end forfeiture risk.
The flat truth: same rate, different risk
An HSA and an FSA tax the same dollar the same way. The real decision isn't about which one saves you more percentage-wise on a given contribution; it's about eligibility (only an HDHP unlocks the HSA) and what happens to money you don't spend. If you're HDHP-eligible and can leave the balance alone, the HSA's higher cap, full rollover, and investing option make it the stronger account for the same tax treatment. If you're not HDHP-eligible, or you know exactly what you'll spend this year and want a bigger near-term cushion for care needs the HSA cap doesn't cover, the FSA is a perfectly good pre-tax tool, just one with a deadline attached.
Sources
- 2026 HSA contribution limits ($4,400 self-only, $8,750 family) and the age-55 $1,000 catch-up: IRS Revenue Procedure 2025-19 (PDF).
- 2026 health FSA salary-reduction limit ($3,400) and maximum carryover ($680): IRS Revenue Procedure 2025-32, Section 4.15 (PDF).
- HSA rules, the triple tax advantage, use-it-or-lose-it FSA treatment, and cafeteria-plan payroll (FICA) tax treatment: IRS Publication 969, Health Savings Accounts and Other Tax-Favored Health Plans.
- FICA payroll tax rate (7.65% employee share of Social Security and Medicare) applied to cafeteria-plan and payroll-deducted HSA contributions: IRS Publication 15 (Circular E), Employer's Tax Guide.
- California does not conform to federal HSA tax treatment; contributions are not deductible and earnings are taxed as earned for state purposes: California FTB, 2025 Instructions for Schedule CA (540).
- Federal marginal tax rates and payroll (FICA) tax rules vary by income, filing status, and employer plan; the calculator's figures are illustrative math based on the rate and status you enter, not a tax return.