FSA and HSA are not the same, though both let you set aside pre-tax money for medical costs

A Flexible Spending Account (FSA) and a Health Savings Account (HSA) both reduce your taxable income by letting you pay for medical expenses with money that hasn't been taxed yet. But they work under different rules, have different limits, and serve different purposes. The main difference: an HSA is yours to keep and grow indefinitely, while an FSA is tied to your job and you typically lose unspent money at the end of the year.

Understanding which one you have access to—and how each one works—matters because the wrong choice or the wrong strategy can cost you money. Many people have access to only one, but some employers offer both, and knowing the trade-offs helps you use whichever account you have more effectively.

Key Takeaways

  • An FSA is employer-sponsored and money left unspent at year-end is forfeited, while an HSA is portable, belongs to you permanently, and rolls over year to year.
  • HSAs require enrollment in a high-deductible health plan (HDHP), while FSAs work with any health insurance plan your employer offers.
  • HSA contribution limits are higher than FSA limits, and HSAs can be invested to grow like a retirement account.
  • FSAs let you set aside money for dependent care and transit costs in addition to medical expenses, while HSAs cover medical expenses only.
  • Both accounts reduce your taxable income and let you avoid payroll taxes on money spent on covered medical costs.

How FSA and HSA contributions work differently

With an FSA, you decide how much to contribute during your employer's open enrollment period, and that money is deducted from your paycheck before taxes. Your employer may also contribute to your FSA. The money sits in an account managed by your employer's benefits administrator, and you spend it on covered medical costs throughout the year.

An HSA works the same way in terms of tax treatment—contributions come out pre-tax—but the account is yours individually, not tied to your job. You can open an HSA through your employer's plan or on your own through a bank or investment firm. You control the account, and you can take it with you if you change jobs. The money doesn't disappear at the end of the year; it stays in the account and grows.

FSA contribution limits are set by the IRS and change yearly; the limit is lower than HSA limits. HSA limits are also set by the IRS and vary depending on whether you have individual or family coverage. Because HSAs roll over indefinitely, you can accumulate a large balance over time if you don't spend the money.

The use-it-or-lose-it rule and what it means for your money

The most significant practical difference between the two accounts is what happens to unspent money. FSAs operate under a use-it-or-lose-it rule: money you don't spend by the end of the plan year is forfeited and goes back to your employer. This means you need to estimate carefully how much medical expense you'll have and contribute only what you're confident you'll use.

Some employers offer a grace period—usually two and a half months into the next year—during which you can still spend money from the previous year's FSA. A few employers also allow a limited carryover of up to $610 (the amount changes yearly) into the next year. But most FSAs have no grace period and no carryover, so unspent money is simply lost.

HSAs have no use-it-or-lose-it rule. Money you don't spend stays in the account forever. You can let it accumulate, spend it years later, or even invest it in mutual funds or stocks to grow it like a retirement account. This makes HSAs much more flexible for long-term planning.

Which insurance plans may have access to for each account

An FSA works with any health insurance plan your employer offers—whether it's a low-deductible plan, a high-deductible plan, or anything in between. Your employer decides whether to offer an FSA, and if they do, you can enroll during open enrollment.

An HSA requires that you be enrolled in a high-deductible health plan (HDHP). The IRS defines what qualifies as an HDHP based on deductible amounts and out-of-pocket limits, which change yearly. If your employer doesn't offer an HDHP, you cannot open an HSA through them. You could open one independently if you buy an HDHP on the individual market, but most people access HSAs through their employer.

Some employers offer both an FSA and an HDHP with an HSA option. In that case, you typically cannot enroll in both the FSA and the HSA in the same year—you have to choose one. The exception is a limited-purpose FSA, which covers only dental, vision, and hearing expenses; you can pair that with an HSA.

What expenses each account covers

Both FSAs and HSAs cover the same core medical expenses: doctor visits, prescriptions, dental work, vision care, mental health treatment, and many other costs defined by the IRS as may have access to medical expenses. You can use either account to pay deductibles, copays, and coinsurance.

FSAs have one major advantage: they also cover dependent care expenses (childcare, adult day care) and transit costs (parking, public transportation to work). You can set up separate FSA accounts for these categories. HSAs cover medical expenses only, so if you need to set aside pre-tax money for childcare, an FSA is your only option through your employer.

Both accounts exclude expenses that aren't medically necessary—cosmetic procedures, gym memberships, and over-the-counter medications (with some exceptions). The IRS publishes a detailed list of what qualifies, and the rules can be specific and sometimes surprising.

Portability and what happens when you leave your job

When you leave your job, your FSA ends. You have a limited window—usually 60 to 90 days—to spend any remaining balance on covered expenses. After that, any unspent money is forfeited. You cannot take your FSA with you to a new employer or convert it to a personal account.

An HSA is completely portable. It belongs to you, not your employer. When you leave your job, the account stays yours. You can continue to use it, add money to it (if you remain enrolled in an HDHP), invest it, or leave it untouched. If you change jobs and your new employer offers an HSA, you can keep your old account or open a new one—the choice is yours. This portability is one reason HSAs are often called a retirement savings tool.

Investment options and long-term growth

Most FSAs do not allow you to invest the money. Your balance sits in a cash account, and you earn little to no interest. The account is designed for spending within the year, not for growth.

Many HSAs allow you to invest your balance in mutual funds, stocks, or other securities once your balance reaches a certain threshold (often $1,000 to $2,500, depending on the provider). This means you can grow your HSA balance over time through investment returns. Some people use HSAs as a secondary retirement account, letting the money grow untouched and only withdrawing for medical expenses in later years. If you withdraw for non-medical expenses before age 65, you pay income tax plus a 20% penalty; after 65, you pay income tax only (like a traditional IRA).

Frequently Asked Questions

Can I have both an FSA and an HSA at the same time?

Not in the same year, with one exception. If you enroll in an FSA and an HDHP with an HSA, you must choose one. However, if your employer offers a limited-purpose FSA (covering only dental, vision, and hearing), you can pair that with an HSA in the same year. Check with your employer's benefits administrator about what options they offer.

What happens to my FSA if I don't spend all the money by the end of the year?

You lose it. The money is forfeited and returned to your employer. Some employers offer a grace period of up to two and a half months into the next year, or allow a small carryover (usually up to $610), but most do not. This is why estimating your medical expenses carefully is important when you enroll in an FSA.

Can I use my HSA to pay for my spouse's medical expenses?

Yes. HSA money can be used for may have access to medical expenses of you, your spouse, and your dependents, regardless of whether they are covered under your health plan. FSA rules are the same—the account covers family members' medical costs even if they are not enrolled in your plan.

What if I change jobs—can I keep my HSA?

Yes. Your HSA is yours to keep. You can continue using it, adding money to it if your new employer offers an HDHP, or simply let it sit and grow. You cannot do this with an FSA; it ends when you leave your job.

Is an HSA better than an FSA?

It depends on your situation. An HSA offers more flexibility, portability, and long-term growth potential, making it better if you plan to stay healthy and let money accumulate. An FSA is better if you have predictable medical expenses each year and want to use pre-tax money without worrying about investing. If your employer offers both, choose based on your expected spending and whether you value the ability to carry money forward.