HSA vs FSA
Triple-tax-advantaged HSA vs use-it-or-lose-it FSA - which healthcare account wins?
TLDR
HSA = triple tax-free, rolls over forever, you keep it when you leave the job, can invest and grow tax-free. Requires being on a High Deductible Health Plan. FSA = pre-tax, but use-it-or-lose-it within plan year (with small carryover), tied to employer. HSA is the better account by every measure except eligibility - HDHPs aren't right for everyone.
Side-by-side comparison
| Criterion | HSA | FSA | Winner |
|---|---|---|---|
| Eligibility | Must be on an HDHP | Any employer plan | FSA |
| Tax on contribution | Pre-tax / above-the-line deduction | Pre-tax (payroll deduction) | Tie |
| Tax on growth | Tax-free | N/A (cash account) | HSA |
| Tax on qualified withdrawal | Tax-free | Tax-free | Tie |
| 2026 contribution limit (single) | $4,400 | $3,300 | HSA |
| 2026 contribution limit (family) | $8,750 | $3,300 (per employee) | HSA |
| Catch-up (55+) | $1,000 | None | HSA |
| Rollover | Unlimited - rolls forever | Up to $660 (2026); rest is forfeited | HSA |
| Portability | Yours - move with you across jobs | Lost when you leave employer | HSA |
| Investment options | Yes - any approved fund/stock | No - cash only | HSA |
| Retirement use | After 65: any purpose (taxed as income, like Traditional IRA) | Medical only | HSA |
| Employer match | Sometimes (your employer might fund $500-$2K/yr) | Rarely | HSA |
Run your own numbers
Plug in your numbers - the calculator updates instantly. Same math, your inputs.
Estimates only. Returns are not guaranteed. Tax rules and rates current as of 2026-05-16.
When each one wins
When HSA wins
- You're enrolled in (or can switch to) a High Deductible Health Plan (HDHP)
- You can afford to pay current medical bills from cash flow (and let HSA grow)
- You're young / healthy - max HSA, invest in equity, use it as retirement bucket
- You want triple-tax-free wealth (no other account does this)
- Your employer contributes to HSA (free money like 401(k) match)
When FSA wins
- You can't be on an HDHP (e.g., need PPO for chronic condition)
- You have a predictable annual medical spend (childcare, glasses, copays)
- You'd prefer to spend healthcare pre-tax in real time, not save long-term
- Your employer offers FSA but not HSA
- You're maxing other retirement accounts and just want the pre-tax medical discount
The math (typical scenario)
20-year horizon, $3,300/yr contribution (FSA max), 24% bracket, 7% investment growth (HSA only):
HSA ($3,300/yr invested at 7%, untouched) Tax saved on contribution: $792/yr at 24% bracket 20yr corpus: $3,300 * [(1.07^20 - 1) / 0.07] = $135,360 Used for medical at 65+: tax-free Used for non-medical at 65+: taxed as ordinary income (no penalty) Net medical-purchase power: ~$135K (4x your nominal contributions) FSA ($3,300/yr spent on medical each year) Tax saved on contribution: $792/yr at 24% bracket = $15,840 total Account balance at end of year: typically $0 (use-it-or-lose-it) Net long-term value: $0 corpus, but $15K cumulative tax savings on spent medical Difference: HSA gives you $135K of tax-free medical/retirement wealth. FSA gives you the same $15K tax savings but zero retained wealth.
The HSA as a stealth retirement account
Triple-tax-free advantage
HSAs are unique: deductible going in (like Traditional IRA), tax-free growth (like Roth IRA), tax-free withdrawal for medical (like neither). 401(k)s are double-tax-free (in OR out). Roth IRAs are double-tax-free (out only). HSA is triple. This compounds dramatically over 20-30 years.
Pay medical bills out-of-pocket, save receipts
Pro move: don't actually use HSA for current medical bills. Pay out of pocket, save receipts in a folder, let HSA grow tax-free. In retirement (or anytime later), reimburse yourself for those decades-old expenses - tax-free withdrawal, no time limit.
After 65, HSA becomes a backdoor Traditional IRA
After 65, you can withdraw HSA funds for ANY purpose, taxed as ordinary income (like Traditional IRA). No 20% penalty (which applies before 65 for non-medical). So worst case, HSA = Traditional IRA. Best case, HSA = best retirement account ever.
Limited Purpose FSA combo
If you have both HSA-eligible HDHP AND want some pre-tax dental/vision spending, you can do a 'Limited Purpose FSA' alongside HSA. LPFSA only covers dental/vision; HSA covers everything else.
Frequently asked questions
Can I have both an HSA and an FSA?
Not a full FSA - that disqualifies HSA eligibility. But you can pair HSA with a Limited Purpose FSA (covers only dental/vision).
What happens to my HSA when I change jobs?
It's yours forever. The funds and the account stay with you, you just stop the employer contribution. You can keep using the same custodian or roll to another.
What if I'm enrolled in Medicare?
You can't contribute to an HSA once enrolled in Medicare. But you CAN keep using the existing HSA tax-free for medical.
Is the FSA $660 carryover automatic?
It's an employer option. Many employers offer it but some require you to use 100% within the plan year. Check your plan documents.
Can I use HSA for dental, vision, mental health?
Yes - all qualified medical expenses including dental, vision, mental health, addiction treatment, fertility, and prescription drugs. Cosmetic procedures don't qualify.
Is gym membership covered?
Generally no, but doctor-prescribed exercise programs for specific conditions may be. The IRS Publication 502[1] lists qualified expenses.
What's the penalty for non-medical HSA withdrawal before 65?
Tax + 20% penalty. After 65, just tax (no penalty).
Can I use HSA to pay for my child's medical?
Yes - HSA can pay for any tax dependent's medical, including children, spouse, and qualifying relatives.
Does HSA reduce my FICA tax?
Yes if contributed via payroll (Section 125 cafeteria plan). Your contribution is exempt from both income tax AND FICA - that's an extra 7.65% tax savings.
Should I max HSA before 401(k)?
After capturing 401(k) employer match, HSA usually wins next (triple tax-free beats double tax-free). Then back to 401(k) for the higher limit.