An FSA and a medical savings account are not the same thing, and the difference matters for your taxes and your money

A Flexible Spending Account (FSA) is an employer-sponsored plan where you set aside pre-tax dollars to pay for may have access to medical expenses. A Health Savings Account (HSA) is the closest thing to what people mean by "medical savings account"—it's also funded with pre-tax money, but you own it, it rolls over year to year, and you can invest it. They're both tax-advantaged, but they work in completely different ways and have opposite rules about what happens to money you don't spend.

The confusion happens because both let you use pre-tax dollars for medical bills. But an FSA is "use it or lose it"—money left over at the end of the year is gone. An HSA is yours to keep forever, and you can withdraw it tax-free only for medical expenses. If you have an FSA through your employer, you cannot also have an HSA in the same year, which is the rule that trips up most people.

Key Takeaways

  • An FSA is employer-run and money you don't spend by the end of the year is forfeited, while an HSA is your personal account that grows year to year and you keep the balance forever.
  • FSA contributions are deducted from your paycheck before taxes, lowering your taxable income, but you must spend the money within the plan year or lose it (with a small carryover grace period in some plans).
  • You can only have an HSA if you're enrolled in a high-deductible health plan (HDHP), but you can have an FSA with almost any employer health insurance.
  • If your employer offers an FSA, you cannot contribute to an HSA in the same year, even if you have an HDHP.

How an FSA works and what you can spend it on

You elect an FSA amount during your employer's open enrollment period—usually once a year in the fall. That money is deducted from your paycheck before taxes, which lowers your taxable income for the year. You get a debit card or submit receipts to reimburse yourself for may have access to medical expenses: copays, deductibles, prescription drugs, dental work, vision care, and medical equipment like crutches or glucose monitors.

The catch is the important date. Your plan year typically runs January through December. Any money left unspent by December 31 is forfeited—your employer keeps it. Some employers offer a grace period (usually 2.5 months into the next year) or let you carry over up to $610 (the 2024 limit), but most do not. You have to estimate how much you'll spend and commit to that number. If you guess wrong and don't spend it, the money is gone.

Because of this rule, most people contribute small amounts—$500 to $1,500 a year—to cover predictable costs like copays or prescription refills. Contributing more than you'll actually spend is a real financial loss.

How an HSA works and why it's different

An HSA is a personal savings account you own, not your employer. You can only open one if you're enrolled in a high-deductible health plan (HDHP)—a plan with a deductible of at least $1,600 for individual coverage or $3,200 for family coverage (2024 limits). Your employer may contribute to your HSA, you can contribute yourself, or both.

Money in an HSA rolls over year to year. You don't lose it. You can withdraw it tax-free to pay for may have access to medical expenses anytime—this year, next year, or 20 years from now. You can also invest the balance in stocks or bonds, and any growth is tax-free as long as you use it for medical expenses eventually. If you withdraw money for non-medical reasons before age 65, you pay income tax plus a 20% penalty. After 65, you can withdraw for anything without penalty (though non-medical withdrawals are taxed as income).

The tradeoff is that you must be on an HDHP to have an HSA. If your employer offers a traditional PPO or HMO plan, you cannot open an HSA, even if you want to. And if your employer offers both an HDHP and an FSA, you have to choose: you can enroll in the HDHP and contribute to the HSA, or you can take the FSA and give up the HSA for that year.

The "use it or lose it" rule and what it costs you

This is where FSAs hurt. If you contribute $2,000 to an FSA and only spend $1,200, you lose $800. Your employer doesn't refund it, and you don't get a tax deduction for it—it's straightforward gone. This is why FSAs are risky if your medical spending is unpredictable or if you're not sure you'll stay with your employer all year.

Some employers soften this with a grace period—usually 2.5 months into the next calendar year—where you can still submit receipts from the previous year. A few allow a carryover of up to $610 (2024 limit). But most do not offer either option. Check your plan documents to see what your employer allows.

An HSA has no such penalty. Unspent money stays in your account. This makes an HSA much better for long-term medical savings, especially if you're young and healthy and don't expect to use much of it this year.

When an FSA makes sense despite the risk

An FSA is worth using if you have predictable, regular medical expenses: monthly prescription copays, ongoing dental work, or vision care you know you'll need. If you can estimate your spending within a few hundred dollars, an FSA saves you money on taxes. A $2,000 FSA contribution might save you $400 to $600 in federal and state taxes, depending on your tax bracket.

An FSA also makes sense if you're on a traditional health plan (PPO or HMO) and your employer doesn't offer an HSA. In that case, an FSA is your only tax-advantaged way to set aside money for medical costs.

But if your medical spending is unpredictable—if you might need expensive tests or procedures but aren't sure when—an HSA is safer. You're not betting that you'll spend a specific amount by a specific date.

Can you have both an FSA and an HSA?

No, not in the same year. If your employer offers both an HDHP (which qualifies you for an HSA) and an FSA, you must choose one. If you enroll in the HDHP and open an HSA, you cannot contribute to the FSA. If you choose the FSA, you cannot open an HSA that year, even if you have an HDHP.

The only exception is a Limited-Purpose FSA (also called a dependent care FSA or a dental/vision-only FSA). Some employers let you pair a Limited-Purpose FSA with an HSA because the FSA covers only specific expenses that the HSA doesn't. But this is rare, and you need to check your employer's plan to see if it's allowed.

If you leave your job and lose access to the FSA, you can open an HSA later in the same year if you enroll in an HDHP. The HSA contribution limit is prorated based on how many months you're may be able to access, so you won't get the full annual contribution, but you can start building the account.

What may have access to medical expenses mean in both accounts

Both FSAs and HSAs cover the same list of may have access to expenses, defined by the IRS. This includes copays, coinsurance, deductibles, prescription drugs, dental work, vision care, hearing aids, crutches, wheelchairs, and many other items. Over-the-counter medications like pain relievers or allergy medicine are covered only if you have a prescription (this changed in 2020).

What's not covered: cosmetic procedures, gym memberships, vitamins (unless prescribed for a specific condition), and most wellness products. Health insurance premiums are not covered, and neither is long-term care insurance. If you're unsure whether something qualifies, the IRS publishes a full list, and your plan administrator can tell you whether a specific expense is allowed.

The may have access to expense list is the same for both accounts, so the difference between an FSA and an HSA is not about what you can buy—it's about whether you keep the money if you don't spend it.

Frequently Asked Questions

What happens to my FSA money if I leave my job?

You lose it. FSA money belongs to your employer's plan, not to you. When you leave, any unspent balance is forfeited. You have a short window (usually 30 to 60 days) to submit receipts for expenses you incurred before you left, but once that important date passes, the money is gone. This is one reason HSAs are better if you change jobs frequently.

Can I use my FSA debit card for anything, or only medical expenses?

Only may have access to medical expenses. The debit card is restricted to pharmacies, doctors' offices, and medical suppliers. If you try to use it at a grocery store or gas station, it will be declined. Some cards have a "store-level" restriction that blocks certain merchants entirely.

How much can I contribute to an FSA?

The annual limit is $3,300 for 2024 (this limit changes yearly). Your employer may set a lower limit. You elect the amount during open enrollment, and it's deducted from your paycheck in equal installments throughout the year. You cannot change your election mid-year unless you have a may have access to life event like a birth, marriage, or loss of other health coverage.

Is an HSA better than an FSA?

It depends on your situation. An HSA is better if your medical spending is unpredictable or if you want to save for future medical costs—you keep the money forever and can invest it. An FSA is better if you have predictable, regular expenses and want to save on taxes this year without worrying about investing. If your employer offers only an FSA, that's your choice. If they offer both, compare your expected spending against the risk of losing unspent FSA money.

Can I withdraw from my HSA for non-medical reasons?

Yes, but it costs you. Before age 65, non-medical withdrawals are subject to income tax plus a 20% penalty. After 65, you can withdraw for any reason without penalty, but non-medical withdrawals are taxed as regular income. This makes an HSA less useful as a general savings account, though some people use it that way and accept the tax hit.