Open enrollment season drops both of these acronyms on you at once, and most people just pick whichever one their coworker mentioned last. That's a shame, because FSAs and HSAs — despite both dangling the same pre-tax carrot — work almost nothing alike once you actually use them.
FSA vs HSA: The Core Differences
| Factor | FSA | HSA |
|---|---|---|
| Eligibility | Any employer plan | Must have HDHP |
| Rollover | Use it or lose it* | Rolls over forever |
| Ownership | Employer owns it | You own it |
| Investment Option | No | Yes (after threshold) |
| Portable on Job Change | No | Yes |
| 2026 Limit | $3,400 | $4,400 / $8,750 |
*FSAs now allow up to a $680 rollover, or a 2.5-month grace period, at the employer's discretion.
The HSA Triple Tax Advantage
The HSA is arguably the most tax-efficient account in the US tax code — offering three simultaneous tax benefits no other account provides:
- Contributions are pre-tax (reduce your taxable income — like a 401k)
- Growth is tax-free (invest the balance and pay no tax on gains)
- Withdrawals are tax-free for qualified medical expenses (unlike a 401k)
After age 65, HSA funds can be withdrawn for any purpose and are taxed as ordinary income — making it function identically to a Traditional IRA as a backup retirement account.
FSA Rules You Need to Know
The FSA's major limitation: use-it-or-lose-it. Funds not used by year-end (plus grace period or rollover amount) are forfeited to the employer. This means careful planning is essential — estimate your medical expenses conservatively to avoid losing money. One advantage: the full year's FSA contribution is available on January 1 — you can use $3,400 on January 2 even though you haven't contributed that much yet.
💡 In December, check your FSA balance. Eligible expenses to spend remaining funds: glasses, contacts, dental work, eligible OTC medications, and many medical supplies available on your plan's eligibility list.
2026 Contribution Limits
HSA limits (2026): Individual HDHP coverage: $4,400. Family HDHP coverage: $8,750. Catch-up contribution (age 55+): additional $1,000. To qualify for an HSA, your health plan must meet HDHP minimums: deductible of at least $1,700 (individual) or $3,400 (family).
FSA limits (2026): $3,400 individual (employer can set it lower), with up to $680 allowed to roll over. Dependent Care FSA (for childcare): jumped to $7,500 per household under the new law, up from $5,000 previously. FSA and HSA cannot be combined unless the FSA is a Limited-Purpose FSA (dental and vision only).
Which Should You Choose?
Choose HSA when: you're generally healthy, can afford the higher HDHP deductible if needed, want to invest the balance long-term, or change jobs frequently (HSA travels with you). Choose FSA when: you have predictable, significant medical expenses each year and your employer doesn't offer an HDHP, or you want access to the full year's funds immediately.
Quick Checklist
- Check if your health plan qualifies for an HSA (must be an HDHP)
- Invest HSA funds rather than leaving them in cash — most plans allow this above a minimum balance
- Track FSA balance monthly to avoid year-end forfeitures
- Use Limited-Purpose FSA + HSA together if your plan allows it
- Contribute to HSA even if you don't plan to use it — invest it as a medical retirement fund
- Save all medical receipts — you can reimburse yourself from HSA years later with no deadline
For informational purposes only. Not financial, tax, or legal advice. Consult a qualified professional before making major decisions.