Can I have both an HSA and an FSA?

Generally no. If you have an HSA, you can typically only pair it with a Limited Purpose FSA (dental and vision only) or a Dependent Care FSA, not a general-purpose Health FSA, because the IRS considers a regular FSA disqualifying coverage for HSA eligibility.

What happens to unused FSA money at year end?

Most Health FSAs are use-it-or-lose-it. Employers may offer either a grace period of up to 2.5 extra months or a carryover of up to $640 (2024 limit) into the next year, but not both, and many plans offer neither.

Does HSA money roll over every year?

Yes, 100% of unused HSA funds roll over indefinitely with no expiration and no forfeiture, unlike most FSAs. The account is yours permanently, even after you leave your employer.

Do I need a High Deductible Health Plan to get an HSA?

Yes. You must be enrolled in an IRS-qualified High Deductible Health Plan (HDHP) to contribute to an HSA. FSAs have no such requirement and are available with most standard employer health plans.

Can I invest my HSA balance?

Yes. Most HSA providers let you invest balances above a small cash threshold (often $1,000-$2,000) into mutual funds or ETFs, similar to a 401(k). FSAs cannot be invested since the funds must be spent within the plan year.

What can I use HSA funds for after age 65?

After 65, you can withdraw HSA funds for any purpose without the 20% penalty, though non-medical withdrawals are taxed as ordinary income, similar to a traditional 401(k). Medical withdrawals remain tax-free at any age.

HSA vs FSA: Which Is Right for You?

Open enrollment throws a confusing acronym at nearly every US employee: HSA or FSA? Both let you set aside money before taxes to cover medical costs, and both shrink your taxable income on your next salary calculation. But they are built on completely different plumbing. A Health Savings Account (HSA) is a portable, investable account you only qualify for if you're on a high-deductible health plan, while a Flexible Spending Account (FSA) is a use-it-or-mostly-lose-it benefit tied to your current employer. Picking the wrong one — or picking one when the other actually fits your health plan — can cost you hundreds of dollars in forfeited funds or a missed tax shelter.

Side-by-Side Comparison

Criteria	HSA	FSA
Eligibility requirement	Must be enrolled in a High Deductible Health Plan	Any employer-sponsored plan that offers one
2024 contribution limit	$4,150 individual / $8,300 family	$3,200 (Health FSA)
Rollover rules	100% rolls over every year, forever	Up to $640 carryover or 2.5-month grace period, not both, often neither
Ownership after job change	Yours permanently, fully portable	Forfeited when you leave the employer (unless COBRA)
Investment options	Can invest in mutual funds/ETFs like a 401(k)	Cash only, cannot be invested
Funds available on day one	Only what you've actually contributed	Full annual election available immediately
Use for non-medical after 65	Yes, taxed as ordinary income, no penalty	No, forfeited if unused

When to Choose Each

Choose an HSA if...

Your employer offers a high-deductible health plan and you can absorb the higher deductible
You want a long-term, investable tax shelter on top of medical coverage
You expect to stay relatively healthy and want unused funds to compound for decades
You value portability across jobs and eventual use as a retirement account

Choose an FSA if...

Your employer doesn't offer a qualifying HDHP
You have predictable, known medical or dependent-care costs this year
You want your full annual election available from day one, before you've actually funded it
You prefer simplicity over long-term investment management

Worked Example

Say you're in the 22% federal tax bracket and expect $3,000 in medical expenses this year.

Scenario	HSA	FSA
Pre-tax contribution	$3,000	$3,000
Immediate tax savings (22%)	$660	$660
Unused $500 at year end	Rolls over, stays invested	Mostly forfeited
Value after 20 years if left invested at 7%	~$1,935 (on the rolled-over $500)	$0 (funds expired)

Both accounts deliver the same $660 tax savings up front. The real difference shows up when your actual spending comes in under budget: HSA leftovers keep compounding for decades, while FSA leftovers typically vanish. This is illustrative only — actual investment returns and tax savings depend on your real bracket, plan design, and market performance.

💡 Pro tip: If you're eligible for an HSA, many financial planners recommend paying current medical bills out-of-pocket when you can afford to, and letting the HSA balance grow untouched as a stealth retirement account.

Figures above are illustrative estimates only and do not constitute financial, tax, or medical advice. Consult a qualified tax professional or benefits administrator before choosing a plan.