HSA vs FSA: The One Rule That Decides
If you want flexibility, choose HSA. If you want to spend on predictable costs this year, choose FSA.
You've picked your health plan. Now you need to choose your wallet—the account you use to pay for care.
An HSA and an FSA aren't insurance. They're tax-advantaged accounts for paying eligible healthcare costs.
New here? Start with How to Read Any Health Plan and How to Choose a Health Plan first.
The One Rule
HSA = flexibility and future value (if you're eligible). FSA = spend on predictable costs this year.
That's the core decision. Everything else is details.
HSA vs FSA at a Glance
- Money is yours forever — rolls over year to year
- Keep it if you change jobs
- Can invest it for long-term growth
- Requires an HSA-qualified high-deductible plan (HDHP)
- Use-it-or-lose-it (some employers allow small rollover)
- Tied to your employer
- Great for predictable, known expenses
- Works with most health plan types
Choose in 2 Minutes
- You have (or want) an HSA-qualified HDHP
- You like money that rolls over
- You can handle the deductible if something happens early
- You want flexibility for future medical costs
- You have predictable expenses (prescriptions, therapy, dental)
- You want to pre-fund this year's healthcare
- You can estimate your spending reasonably well
- You don't qualify for an HSA
Still stuck? Ask yourself: Would I rather keep money for later (HSA) or force myself to spend on healthcare now (FSA)?
Quick Eligibility Check
- Enrolled in an HSA-qualified HDHP
- No disqualifying other coverage
- Not enrolled in Medicare
FSA eligibility: If your employer offers it, you can usually enroll regardless of plan type.
Not sure if you qualify for an HSA? Use the HSA Eligibility Checklist.
How Much to Contribute
- Add up: prescriptions, copays, planned dental/vision
- Only contribute what you're confident you'll spend
- When in doubt, go lower
- Build enough to cover a chunk of your deductible
- Then decide: spend as you go, or let it grow
- No pressure — unused money stays yours
Mistakes to Avoid
Overfunding an FSA. If you don't spend it, you lose it. Fund conservatively.
Choosing HDHP just for the HSA. The plan still needs to work for your year. A high deductible can hurt if you need a lot of care.
What's Next
Now that you understand the HSA vs FSA decision, you're ready to enroll with confidence.
Need help deciding between HSA and FSA?
This article is for educational purposes only and does not constitute tax, legal, or medical advice.
Frequently Asked Questions
Can I have both an HSA and FSA?
What happens to my HSA if I change jobs?
What happens to my FSA if I don't spend it all?
Is an HSA always better?
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