HSA vs FSA: What's the Difference? (2026 Guide)

Short answer: An HSA (Health Savings Account) is yours forever, rolls over every year, and requires a high-deductible health plan. An FSA (Flexible Spending Account) is use-it-or-lose-it, tied to your employer, and works with any health plan. HSAs are generally better for long-term savings; FSAs are simpler if you know exactly what you'll spend.

The Basics

HSA (Health Savings Account): A tax-advantaged savings account you own. Contributions are pre-tax, growth is tax-free, and withdrawals for qualified medical expenses are tax-free. Funds roll over indefinitely. You keep it even if you change jobs. FSA (Flexible Spending Account): An employer-sponsored account that lets you set aside pre-tax money for medical expenses. Funds generally must be used within the plan year or you lose them. The account belongs to your employer's plan, not you.

Side-by-Side Comparison

Feature	HSA	FSA
2026 contribution limit (individual)	$4,400	$3,300
2026 contribution limit (family)	$8,750	$3,300 (per employee)
Rollover	✅ Unlimited — funds never expire	⚠️ Limited — $640 max or 2.5-month grace period
Portability	✅ You own it forever	❌ Tied to your employer
Eligibility	Must have HDHP	Any employer health plan
Employer contributions	✅ Allowed	✅ Allowed
Investment options	✅ Yes	❌ No
Catch-up contributions (55+)	+$1,000	❌ None
Can change mid-year	✅ Anytime	❌ Only during open enrollment or qualifying event
Tax benefit	Triple tax advantage	Pre-tax contributions only

The Triple Tax Advantage (HSA Only)

HSAs are the only account in the US tax code with a triple tax benefit:

Tax-free contributions — reduce your taxable income

Tax-free growth — investments grow without capital gains tax

Tax-free withdrawals — no tax when used for qualified medical expenses

FSAs only offer benefit #1. There's no investment option and no growth.

The Use-It-or-Lose-It Problem

This is the FSA's biggest downside. If you put $3,000 into your FSA and only spend $2,000, you lose $1,000. Gone.

Employers can offer one of two relief options (but not both):

• Rollover: Up to $640 carries into the next year
• Grace period: 2.5 extra months to spend remaining funds

Even with these options, FSAs require you to predict your medical expenses accurately. Overestimate and you lose money. Underestimate and you miss out on tax savings.

HSAs have no such restriction. Unspent funds roll over forever. You can contribute for decades and build a substantial medical nest egg.

Eligibility: Who Can Open What?

HSA eligibility requires:

• Enrollment in an HSA-eligible high-deductible health plan (HDHP)
• 2026 minimum deductible: $1,700 (individual) / $3,400 (family)
• 2026 max out-of-pocket: $8,500 (individual) / $17,000 (family)
• No other health coverage (with some exceptions)
• Not enrolled in Medicare
• Not claimed as a dependent

FSA eligibility:

• Your employer offers an FSA plan
• That's basically it

If you have a low-deductible health plan, an FSA may be your only option. If you have an HDHP, you can choose an HSA (and sometimes a limited-purpose FSA alongside it).

Can You Have Both?

Generally, no — you can't have a regular FSA and an HSA at the same time. However, you _can_ pair an HSA with a limited-purpose FSA (LP-FSA), which covers only dental and vision expenses.

This combo is actually powerful: use the LP-FSA for dental and vision, and keep your HSA funds for everything else (or invest them for the long term).

Which Is Better for Wellness Spending?

Neither a traditional HSA nor an FSA directly supports wellness spending like gym memberships and supplements. However, with a Letter of Medical Necessity (LMN), wellness expenses can become qualified medical expenses for both account types.

Hammock makes this easy by including unlimited LMNs with its HSA and also supporting FSA funds — so regardless of which account type you have, you can use pre-tax dollars for wellness.

When to Choose an HSA

• You have (or can get) a high-deductible health plan
• You want funds that roll over and grow
• You want to invest for long-term medical expenses
• You want portability (not tied to your employer)
• You're relatively healthy and don't have high annual medical costs

When to Choose an FSA

• You don't have (or don't want) a high-deductible health plan
• You can accurately predict your annual medical expenses
• You want the simplest option your employer offers
• You have predictable recurring medical costs (prescriptions, therapy, etc.)

Frequently Asked Questions

What happens to my FSA if I leave my job?

You typically lose access to any remaining FSA funds when your employment ends. Some plans offer COBRA continuation, but it's often not worth the cost.

Can I contribute to an HSA without an employer?

Yes. HSAs are individual accounts. You can open and contribute to an HSA on your own, as long as you have an eligible HDHP. Self-employed individuals can also deduct HSA contributions.

What's the penalty for non-medical HSA withdrawals?

Before age 65, non-medical withdrawals are subject to income tax plus a 20% penalty. After 65, you pay only income tax (similar to a traditional IRA).

Do HSA contributions reduce my Social Security taxes?

Payroll HSA contributions (through your employer) reduce both income tax and FICA taxes. Direct contributions only reduce income tax.

Can I use last year's FSA money for this year's expenses?

Only if your employer offers a rollover (up to $640) or a grace period (2.5 months). Check your plan documents.

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Ready to start using your HSA for wellness? Hammock includes unlimited Letters of Medical Necessity — so your gym, supplements, and massage are all tax-free.