How FSA Accounts Work: The Money Flow and the Rules

How an FSA account actually works

A Flexible Spending Account (FSA) is a payroll deduction account your employer sets up. You decide how much to set aside from your paycheck each year — up to $3,300 for 2024 — and that money goes into a separate account before taxes are taken out. When you have a medical or dependent care expense, you pay for it out of pocket, then submit a receipt to your FSA administrator and they reimburse you from the account.

The tax savings come from the fact that the money you put in never gets taxed as income. If you earn $50,000 and contribute $2,500 to an FSA, you only pay income tax on $47,500. That's the entire point: you reduce your taxable income, which means you owe less in federal income tax, Social Security tax, and Medicare tax.

Your FSA administrator is usually a third-party company your employer hires — names like WageWorks, Conduent, or HealthEquity. They hold the money, process your reimbursement requests, and send you a debit card or check. You don't manage the account yourself; you just submit claims when you spend.

Key Takeaways

• You choose how much to contribute each year during open enrollment, and that amount is deducted from your paychecks before taxes are calculated.
• You pay for may be able to access medical or dependent care expenses yourself, then submit receipts to your FSA administrator for reimbursement.
• The money you contribute is not subject to federal income tax, Social Security tax, or Medicare tax, which is where your savings come from.
• Most FSAs have a "use it or lose it" rule: money left over at the end of the year is forfeited, though your employer may offer a grace period or carryover option.
• Your FSA is tied to your job — if you leave your employer, you lose access to the account and any remaining balance.

What counts as an may be able to access FSA expense

The IRS publishes a list of what you can spend FSA money on. For a medical FSA, may be able to access expenses include copays, coinsurance, deductibles, prescription medications, dental work, vision care, and certain medical equipment like crutches or blood pressure monitors. Over-the-counter medications are may be able to access only if you have a prescription for them — aspirin and cold medicine bought without a prescription do not count.

Dependent care FSAs cover a narrower range: daycare, preschool, after-school programs, and summer day camps for children under 13. They also cover adult day care for a dependent adult. What they do not cover: overnight camps, tuition for kindergarten and above, or babysitting for leisure purposes (only for work-related childcare).

The IRS rules are strict. Cosmetic procedures, gym memberships, vitamins without a medical condition, and most wellness programs do not may have access to. If you're unsure whether something counts, your FSA administrator can tell you before you spend the money — most have a customer service line or online tool to check.

How to submit a claim and get reimbursed

When you have an may be able to access expense, you pay for it yourself. Then you gather the receipt or explanation of benefits (EOB) from your provider and submit it to your FSA administrator. Most administrators now accept online submission through a website or mobile app — you photograph the receipt and upload it. Some still accept paper claims by mail.

The administrator reviews the receipt to make sure the expense is may be able to access and the amount matches what you claimed. If everything is in order, they reimburse you within a few business days, usually by depositing money into a linked bank account or loading it onto a debit card. If the receipt is unclear or the expense is not may be able to access, they'll ask you for more information or deny the claim.

Keep all receipts for at least three years. The IRS can audit FSA claims, and you need documentation to prove the money went to may be able to access expenses. Some administrators now offer "substantiation-free" debit cards that don't require you to submit receipts for every purchase, but you still need to keep them in case of an audit.

The use-it-or-lose-it rule and what happens to leftover money

This is the most important rule to understand: money left in your FSA at the end of the plan year is forfeited. If you contribute $2,500 and only spend $1,800, you lose the remaining $700. There is no rollover to next year, no refund, and no exception — the money goes back to your employer or the insurance pool.

Because of this rule, you need to estimate carefully how much you'll actually spend in the coming year. Look at your medical bills from the past two years, add in any planned procedures, and be conservative. It's better to contribute less and miss out on some tax savings than to contribute too much and forfeit money.

Some employers offer a grace period of up to 2.5 months after the plan year ends, during which you can still submit claims for expenses incurred in the previous year. Others offer a carryover of up to $640 (for 2024) that rolls into the next year's account. Ask your employer which option they provide — not all do. If your employer offers neither, the use-it-or-lose-it rule applies strictly.

FSA debit cards and how they work

Many FSA administrators issue a debit card that draws directly from your FSA balance. You can use it at pharmacies, doctors' offices, and other medical providers that accept it. The card is linked to your account, so the transaction is tracked automatically.

The catch: the debit card can only be used at merchants that are coded as medical or dependent care providers. You can't use it at a grocery store to buy over-the-counter medicine, even though some OTC items are FSA-may be able to access. If you try, the card will be declined. For those purchases, you have to pay out of pocket and submit a receipt for reimbursement.

Some administrators require you to submit a receipt even when you use the debit card, especially for large purchases or categories that are sometimes ineligible. This is called "substantiation" and it protects both you and the administrator from IRS scrutiny. Check with your administrator about their specific policy.

What happens to your FSA when you leave your job

Your FSA is an employer-sponsored benefit, which means it ends when your employment ends. You cannot take the account with you or transfer the balance to a new employer's FSA. Any money remaining in the account is forfeited, even if you leave mid-year.

However, you have 60 days after leaving your job to submit claims for expenses you incurred while you were employed. After that window closes, you cannot access the account. This is why it's important to gather all your receipts from the year and submit them quickly if you know you're leaving.

If you move to a new job with a different employer that also offers an FSA, you can enroll in their plan during your new-hire enrollment period. You start fresh with a new contribution amount and a new plan year. The two accounts are completely separate.

FSA vs. HSA: which one you might have instead

If your employer offers a Health Savings Account (HSA), you may not be able to have an FSA at the same time. HSAs are only available to people enrolled in a high-deductible health plan (HDHP), and they have different rules: the money rolls over year to year, you can invest it, and you can use it for retirement. FSAs are simpler but have the use-it-or-lose-it rule.

Some employers offer both an FSA and an HSA to different employees based on their health plan choice. Others offer only one. If you have a choice, compare the two: an HSA is better if you want to save long-term and you're healthy; an FSA is better if you have predictable annual medical expenses and want to maximize your tax savings right now.

A dependent care FSA is separate from both medical FSAs and HSAs. You can have a dependent care FSA even if you have an HSA or a medical FSA, as long as your employer offers it.

Common mistakes to avoid with your FSA

The biggest mistake is overestimating how much you'll spend and losing money at year-end. The second biggest is forgetting to submit receipts before the deadline and losing reimbursement. Set a reminder on your phone to gather receipts monthly and submit them, rather than waiting until December.

Another common error is assuming something is may be able to access when it's not. Cosmetic dental work, teeth whitening, and most over-the-counter items without a prescription are not covered. Before you spend money expecting reimbursement, check with your administrator or look it up in the IRS Publication 502 (Medical and Dental Expenses).

Finally, don't assume your FSA works the same way as your coworker's. Administrators have different policies on debit card use, grace periods, and substantiation requirements. Read the summary of benefits your employer gave you, or call your administrator's customer service line to understand your specific plan.

Frequently Asked Questions

Can I change my FSA contribution amount during the year?

No, unless you have a may have access to life event: marriage, divorce, birth or adoption of a child, loss of other health coverage, or a significant change in your dependent care costs. If you have a may have access to event, you have 30 to 60 days to change your contribution. Outside of those events, your contribution is locked in for the entire plan year.

What happens if I submit a claim for an ineligible expense?

Your FSA administrator will deny the claim and ask you to provide more information or a different receipt. If you've already been reimbursed for an ineligible expense, the administrator may ask you to repay the money. The IRS can also audit your claims and penalize you if you've been reimbursed for non-may be able to access expenses.

Can I use my FSA for my spouse's medical expenses?

Yes, as long as your spouse is a dependent on your tax return. You can also use it for your children's medical expenses. The expense just has to be may be able to access; the person receiving the care doesn't have to be you.

What if my FSA administrator goes out of business?

Your employer is responsible for ensuring your money is safe and that claims are paid. If an administrator fails, your employer must transfer your account to a new administrator or return your remaining balance. You won't lose the money, but there may be delays in processing claims during the transition.

Can I use my FSA for mental health or therapy?

Yes. Copays for therapy sessions, psychiatrist visits, and mental health medications are all may be able to access FSA expenses. Therapy and counseling prescribed by a healthcare provider count as medical care under IRS rules.