The core difference between FSA and HSA
An FSA (Flexible Spending Account) and an HSA (Health Savings Account) are both tax-advantaged accounts that let you set aside pre-tax money for medical expenses. The money you put in reduces your taxable income for the year. But they work under different rules, have different contribution limits, and serve different purposes.
The biggest practical difference: an HSA is yours to keep and grow year after year, while an FSA has a "use it or lose it" rule — money left over at the end of the plan year typically disappears. An HSA also requires you to be enrolled in a high-deductible health plan (HDHP), while an FSA works with any health insurance plan your employer offers.
Both accounts pay for the same kinds of expenses: copays, deductibles, prescription drugs, dental work, vision care, and many other medical costs. Neither one covers health insurance premiums (with rare exceptions for COBRA or unemployment insurance).
Key Takeaways
- FSA money must be spent within the plan year or you lose it; HSA money rolls over indefinitely and grows like a retirement account.
- HSA requires enrollment in a high-deductible health plan; FSA works with any employer health plan.
- HSA contribution limits are higher than FSA limits, and HSA funds can be invested to earn interest or returns.
- Both accounts use pre-tax dollars, so contributing reduces your taxable income for the year.
- You can only open an FSA through your employer; HSA can be opened through an employer or on your own if you have an HDHP.
How FSA contributions and spending work
You enroll in an FSA during your employer's open enrollment period, usually once a year. You decide how much to contribute for the coming year — the money comes out of your paycheck before taxes are calculated. For 2024, the FSA contribution limit is $3,200 per year (this amount changes annually and varies by year).
You receive a debit card or reimbursement form to pay for medical expenses throughout the year. When you use the card at a pharmacy, doctor's office, or medical supplier, the cost comes directly from your FSA balance. If you pay out of pocket, you can submit receipts to your FSA administrator for reimbursement.
The catch: money left unspent at the end of the plan year is forfeited. Some employers offer a "grace period" of up to 2.5 months into the next year to spend remaining funds, or a limited carryover of up to $610 (this amount changes annually). Check your employer's plan document to see which option applies to you.
How HSA contributions and spending work
You can open an HSA only if you are enrolled in a high-deductible health plan (HDHP) — a plan with a higher deductible and lower premiums than traditional plans. You can open an HSA through your employer if they offer one, or you can open one independently through a bank or financial institution if you have an HDHP from any source.
For 2024, the HSA contribution limit is $4,150 for individual coverage or $8,300 for family coverage (these amounts change annually). Unlike an FSA, you can contribute to an HSA on your own even if your employer does not offer one — you just need proof of HDHP enrollment. The money you contribute is tax-deductible whether it comes from your paycheck or you contribute it yourself.
HSA funds roll over year after year. Any money you do not spend stays in the account and can accumulate indefinitely. Many HSAs allow you to invest the balance in mutual funds or other investments, so your money can grow over time. You can withdraw funds tax-free for may have access to medical expenses at any point in your life.
Contribution limits and tax treatment
| Feature | FSA | HSA |
|---|---|---|
| Annual contribution limit (individual) | $3,200 (2024) | $4,150 (2024) |
| Annual contribution limit (family) | Not applicable | $8,300 (2024) |
| Money rolls over? | No (forfeited or limited carryover) | Yes, indefinitely |
| Can you invest the balance? | No | Yes, typically |
| Requires HDHP? | No | Yes |
| Can you open outside employer? | No | Yes |
Both accounts reduce your taxable income dollar-for-dollar. If you contribute $2,000 to an FSA, your taxable income drops by $2,000. If you contribute $3,000 to an HSA, your taxable income drops by $3,000. This means you pay federal income tax, Social Security tax, and Medicare tax on a smaller income.
Withdrawals from either account for may have access to medical expenses are tax-free. If you withdraw money for a non-medical expense, you owe income tax on that amount plus a 20% penalty (HSA) or it is simply not reimbursed (FSA).
Which account makes sense for your situation
Choose an FSA if you have predictable medical expenses you know you will spend within the year — regular prescriptions, ongoing therapy, dental work you have scheduled, or frequent copays. FSA works well if you are enrolled in a traditional health plan and want to reduce your taxable income without committing to an HDHP. The downside is that unspent money disappears.
Choose an HSA if you want to build a long-term medical savings cushion, have an HDHP available, and can afford to pay some medical costs out of pocket in the short term. HSA is particularly valuable if you are healthy and do not expect to spend all your contributions in the current year — the money can accumulate and grow. HSA also works as a retirement account: after age 65, you can withdraw money for any reason (though non-medical withdrawals are taxed as income).
Some people do both: they enroll in an HSA because their employer offers an HDHP, and they also contribute to an FSA for predictable near-term expenses. This is allowed as long as the FSA is a "limited-purpose FSA" that covers only dental, vision, and preventive care — not general medical expenses.
Frequently Asked Questions
Can I use my FSA or HSA to pay for health insurance premiums?
Generally no. FSA and HSA funds cannot pay for regular health insurance premiums. However, there are narrow exceptions: you can use HSA funds to pay premiums for COBRA continuation coverage, long-term care insurance, or health insurance while you are receiving unemployment benefits. FSA rules are stricter and do not allow these exceptions in most cases.
What happens to my FSA money if I leave my job?
FSA money is tied to your employer's plan. When you leave, you typically lose access to any unspent balance — it does not follow you to a new job. Some employers allow a short "run-out" period after you leave to submit claims for expenses incurred before your departure. HSA money is yours to keep; you can take it with you and continue using it at any time.
Can I withdraw HSA money before I turn 65?
Yes. You can withdraw HSA funds at any age for may have access to medical expenses without penalty or tax. If you withdraw money for a non-medical reason before age 65, you pay income tax on the withdrawal plus a 20% penalty. After age 65, you can withdraw for any reason and pay only income tax (no penalty), though non-medical withdrawals are taxed as regular income.
Do I need receipts to use my FSA or HSA?
For FSA, you typically need a receipt or explanation of benefits to submit for reimbursement if you pay out of pocket. If you use an FSA debit card at a pharmacy or doctor's office, the transaction is usually processed automatically. For HSA, you should keep receipts for your records, though you do not always need to submit them when you withdraw — but the IRS can ask for proof that expenses were may have access to if you are audited.
Can I have both an FSA and HSA at the same time?
Only if the FSA is a "limited-purpose FSA" or "post-deductible FSA" that covers only dental, vision, and preventive care — not general medical expenses. A general-purpose FSA and HSA cannot be active in the same year because the FSA would let you avoid the HDHP's deductible, which defeats the purpose of the HSA structure.