An FSA is not an HSA, though they look similar at first glance

A Flexible Spending Account (FSA) and a Health Savings Account (HSA) are both tax-advantaged accounts for medical expenses, but they work under different rules and belong to different types of health plans. The biggest difference: an FSA is tied to your employer's benefits package and has a "use it or lose it" important date each year, while an HSA is portable, rolls over year to year, and you keep it even if you change jobs. If your employer offers an FSA, you cannot have an HSA in the same year—you have to choose one or the other.

Understanding which account you have matters because the rules for spending, saving, and what happens to unused money are completely different. Many people assume they have an HSA when they actually have an FSA, or vice versa, and then get surprised when they cannot carry money forward or when their account closes.

Key Takeaways

  • An FSA requires you to spend the money within the plan year or lose it, while an HSA lets you roll unused funds forward indefinitely.
  • You can only have an FSA if your employer offers one; an HSA requires enrollment in a high-deductible health plan, which you can open on your own.
  • FSA contributions come only from your paycheck; HSA contributions can come from you, your employer, or both.
  • An FSA closes when you leave your job or change plans, but an HSA stays with you for life and moves with you between employers.

How FSA spending rules differ from HSA rules

The use-it-or-lose-it rule is the defining feature of an FSA. Money you do not spend by December 31 (or by the end of your plan year, if your employer uses a different calendar) is forfeited. Your employer keeps it. There is a small grace period in some plans—up to 2.5 months into the next year—but after that, unspent money is gone. This forces you to estimate your medical expenses carefully each year.

An HSA has no important date. Money rolls over year after year, and you can let it accumulate if you want. You can spend it this year or in 20 years. This makes an HSA function partly like a retirement account for medical expenses, while an FSA is strictly a year-to-year spending tool.

Both accounts cover the same types of expenses: copays, deductibles, prescriptions, dental work, vision care, and many other out-of-pocket medical costs. The IRS publishes a full list, and it is the same for both. The difference is not what you can buy—it is what happens to money you do not spend.

Who can have an FSA and who can have an HSA

An FSA is only available through your employer. If your company offers one, you enroll during open enrollment and contributions come straight from your paycheck before taxes. If your employer does not offer an FSA, you cannot open one on your own. Self-employed people and employees at small companies often have no FSA option.

An HSA requires two things: you must be enrolled in a high-deductible health plan (HDHP), and you must not be covered by any other health insurance that is not an HDHP. You can open an HSA through your employer if they offer an HDHP, or you can open one on your own through a bank or investment firm if you buy an HDHP on the individual market. This flexibility is one reason HSAs are more portable than FSAs.

You cannot have both an FSA and an HSA in the same calendar year. If your employer offers both, you choose one during open enrollment. Some people switch back and forth depending on their expected medical expenses that year, but you cannot hold both simultaneously.

What happens to your FSA or HSA when you leave your job

When you leave your job, your FSA closes. Any unspent money is forfeited, even if you are in the middle of the plan year. This is true whether you quit, are laid off, or move to a new employer. The only exception is if you have a may have access to life event—marriage, birth of a child, loss of other coverage—that lets you access the remaining balance under COBRA or a similar continuation rule, but this is rare and requires specific circumstances.

An HSA stays with you. You own it, not your employer. When you leave your job, the account remains open and the money is still yours. You can take it to a new employer, roll it into a different HSA provider, or leave it where it is. This portability is a major advantage if you change jobs frequently or plan to retire early.

If you have an FSA and are about to leave your job, spend down the account before your last day if you can. Once the account closes, that money is gone.

How much you can contribute to each account

FSA contribution limits are set by the IRS and change annually. For 2024, the limit is $3,200 per year (this varies by year, so check your plan documents for the current limit). You contribute through payroll deduction, and your employer may also contribute, though most do not. The money comes out of your gross pay, so you save on income and payroll taxes.

HSA contribution limits are also set by the IRS and also change annually. For 2024, the limit is $4,150 for individual coverage and $8,300 for family coverage (again, these vary by year). You can contribute, your employer can contribute, or both can. If both contribute, the combined total cannot exceed the annual limit. HSA contributions also reduce your taxable income.

Because FSA money is use-it-or-lose-it, most people contribute conservatively—only what they expect to spend. HSA contributions tend to be higher because the money does not expire and can grow like an investment account.

Investment and growth in FSA versus HSA accounts

Most FSAs do not allow you to invest the money. Your balance sits in a cash account, earning little to no interest. Some employer plans offer a small interest rate, but this is uncommon. The account is designed for spending, not saving or growth.

Many HSAs allow you to invest the balance in mutual funds, stocks, or other securities, similar to a retirement account. This means your HSA can grow over time if you do not spend it all when ready. Some people use their HSA as a long-term medical savings vehicle, letting the balance compound for decades. Not all HSA providers offer investment options, so you may need to shop around or transfer your account to one that does.

This investment potential is another reason HSAs are sometimes called "triple tax-advantaged": contributions are tax-deductible, growth is tax-free, and withdrawals for medical expenses are tax-free. FSAs only get the first benefit—the tax deduction on contributions.

Frequently Asked Questions

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

No. You can only have one in the same calendar year. If your employer offers both, you choose during open enrollment. Some people switch between them year to year based on their expected medical costs, but you cannot hold both simultaneously.

What happens to my FSA money if I do not spend it by the end of the year?

It is forfeited. Your employer keeps it. Some plans offer a grace period of up to 2.5 months into the next year, but after that window closes, unspent money is gone. Check your plan documents to see if your employer offers this grace period.

Can I take my FSA with me if I change jobs?

No. Your FSA closes when you leave your job, and any remaining balance is lost. An HSA, by contrast, stays with you and moves to your new employer or remains in your personal account.

Is an HSA better than an FSA?

It depends on your situation. An HSA is better if you want to save money long-term, change jobs frequently, or invest your balance. An FSA is better if you have predictable annual medical expenses and want to reduce your taxable income without worrying about carrying money forward.

Can I use my FSA or HSA to pay for health insurance premiums?

Generally no, with one exception: you can use HSA funds to pay for health insurance premiums if you are unemployed and receiving unemployment benefits. FSAs cannot be used for premiums in any situation. Both accounts can pay for copays, deductibles, and other out-of-pocket costs, but not the insurance itself.