What an FSA is and how the money flows

A Flexible Spending Account (FSA) is a way to set aside pre-tax money from your paycheck to pay for medical costs that your health insurance doesn't cover. You choose how much to contribute each year, your employer deducts that amount from your paychecks before taxes are calculated, and you use a debit card or submit receipts to withdraw the money when you have a medical expense.

The tax savings come from the fact that the money never gets taxed as income. If you earn $50,000 a year and contribute $3,000 to an FSA, you only pay income tax on $47,000. That means you're paying for medical costs with money that would have gone to federal, state, and sometimes local taxes — usually saving 20 to 40 percent depending on your tax bracket.

Your employer sets up the FSA through a benefits administrator (a company hired to manage the account). You don't open it yourself. Instead, you enroll during your employer's open enrollment period, usually once a year in the fall or winter. The administrator issues you a debit card, handles the paperwork when you submit receipts, and tracks how much you've spent.

Key Takeaways

  • You contribute money before taxes are taken out of your paycheck, which reduces the income tax you owe that year.
  • FSA money can only be spent on specific medical costs: copays, deductibles, prescriptions, dental work, vision care, and some medical equipment, but not health insurance premiums or over-the-counter medicines without a prescription.
  • Any money you don't spend by the end of the plan year is forfeited — you cannot carry it forward or get it back, with rare exceptions for a grace period or carryover your employer may offer.
  • You enroll during your employer's open enrollment period, and the amount you choose stays fixed for the entire year unless you have a may have access to life change like marriage, birth, or job loss.
  • You access the money through a debit card issued by the administrator, or by paying out of pocket and submitting receipts for reimbursement.

What medical costs you can and cannot pay with FSA money

FSA funds cover most out-of-pocket medical costs that your health insurance doesn't pay. This includes copays (the fixed amount you pay at a doctor visit), coinsurance (your share of the cost after insurance pays its part), deductibles (the amount you pay before insurance kicks in), prescription medications, dental work, vision care including glasses and contact lenses, and some medical equipment like crutches, wheelchairs, or blood pressure monitors.

What FSA money cannot cover: health insurance premiums themselves, over-the-counter medicines like cold medicine or pain relievers (unless you have a prescription from a doctor), cosmetic procedures, gym memberships, vitamins, and most toiletries. The IRS publishes a detailed list, but the basic rule is that the cost must be for diagnosis, treatment, or prevention of a medical condition — not general wellness.

If you're unsure whether a specific item qualifies, ask your FSA administrator before you buy it. Some items sit in a gray area, and the administrator can tell you whether they'll reimburse it. Keeping your receipts is essential: most administrators require you to submit proof of the expense, not just the debit card transaction.

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

Money left in your FSA at the end of the plan year does not roll over to the next year. If you contribute $3,000 and spend only $2,500, the remaining $500 is forfeited — you cannot withdraw it, and your employer cannot return it to you. This is called the use-it-or-lose-it rule, and it exists because of federal tax law.

Some employers offer a grace period of up to 2.5 months after the plan year ends, during which you can still submit receipts for expenses you incurred during the plan year. Other employers allow you to carry over up to $640 (this amount changes yearly) into the next year. Check with your employer or benefits administrator to see if either option is available to you — many employers offer neither.

Because of this rule, choosing the right contribution amount is important. Contribute too much and you lose money. Contribute too little and you miss out on tax savings. Most people estimate based on what they spent the previous year, then adjust up or down. If you have a major medical event coming (surgery, orthodontics, new glasses), that's a good year to contribute more.

How to enroll and when you can make changes

You enroll in an FSA during your employer's open enrollment period, which typically happens once a year in the fall or early winter. Your employer sends out information about available plans, including the FSA. You choose how much to contribute for the upcoming year — the amount is deducted evenly from each paycheck.

Once enrollment closes, you cannot change your contribution amount unless you have a may have access to life event. These include marriage, divorce, birth or adoption of a child, death of a spouse or dependent, loss of health insurance coverage, significant change in health care costs, or a substantial change in your employment status. You typically have 30 to 60 days after the event to notify your employer and make the change.

If you change jobs, your FSA does not follow you. The money in your account stays with your former employer's plan through the end of that plan year. You can then enroll in a new FSA at your new employer during their open enrollment period, but any unspent money from your old account is forfeited.

How to access your money: debit card versus reimbursement

Most FSA administrators issue you a debit card that you can use at pharmacies, doctor's offices, and other medical providers. When you swipe the card, the administrator deducts the amount from your FSA balance. This is the fastest way to use your money — no paperwork required at the time of purchase.

Some transactions may require you to submit a receipt after you use the card. For example, if you use the FSA debit card at a pharmacy to buy both prescription medication (may be able to access) and shampoo (not may be able to access), the administrator may ask you to submit a receipt to confirm what you bought. This is called substantiation, and it protects both you and the administrator from tax violations.

Alternatively, you can pay for medical costs out of pocket and then submit receipts to the administrator for reimbursement. You'll need to provide the receipt, a description of the service or item, and the date. Reimbursement usually takes one to two weeks. This method takes more time but can be useful if you don't have the debit card with you or if you're unsure whether an expense will be approved.

How FSA contributions affect your taxes and take-home pay

Because FSA contributions come out before taxes, they reduce your taxable income for the year. If you earn $50,000 and contribute $3,000 to an FSA, you pay federal income tax only on $47,000. You also avoid paying Social Security and Medicare taxes on that $3,000 (though this is a smaller savings).

The trade-off is that your take-home pay is lower in the short term. If you contribute $3,000 over the year, that's roughly $250 per paycheck (depending on how often you're paid) that doesn't appear in your bank account. However, you save that amount in taxes, so your net cost is lower. For example, if you're in the 25 percent tax bracket, a $3,000 FSA contribution costs you only about $2,250 in actual take-home pay, because you save $750 in taxes.

This is why FSAs work best for people who know they'll have medical expenses. If you contribute money and don't spend it, you lose the tax savings and the money itself. If you contribute and do spend it, you've essentially paid for medical care with pre-tax dollars.

FSA versus HSA: when each one makes sense

An HSA (Health Savings Account) and an FSA are both tax-advantaged accounts for medical costs, but they work differently. An HSA is only available if you have a high-deductible health plan, and money rolls over year to year. An FSA is available through most employers with standard health plans, but money does not roll over.

If your employer offers both, you must choose one or the other — you cannot have both in the same year. An HSA makes sense if you have a high-deductible plan and want to save for future medical costs. An FSA makes sense if you have predictable medical expenses each year and want to reduce your taxes on those costs when ready.

If your employer offers only an FSA, that's your option for a tax-advantaged medical account. If your employer offers only an HSA, you can only use it if you're enrolled in a high-deductible plan. Some employers offer both, and some offer neither.

Frequently Asked Questions

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

Any unspent money in your FSA stays with your former employer's plan and is forfeited at the end of that plan year. You cannot transfer it to a new job or withdraw it. However, you may be able to continue coverage under COBRA (a federal law allowing you to stay on your employer's health plan temporarily), which would let you continue using the FSA through the end of the plan year.

Can I use my FSA debit card for anything other than medical costs?

No. The debit card is restricted to may be able to access medical expenses. If you try to use it for non-medical purchases, the transaction will be declined. Some retailers may not have the system set up to process FSA cards, so the card may be declined even for may be able to access purchases — in that case, pay out of pocket and submit a receipt for reimbursement.

What if I estimate my contribution wrong and run out of money before the year ends?

Once you've spent your FSA balance, you cannot access more money until the next plan year. You'll have to pay for medical costs out of pocket for the rest of the year. This is why it's important to estimate conservatively — it's better to have leftover money (which you'll lose) than to run out early.

Can I use FSA money for my spouse or children?

Yes. FSA money can be used for may be able to access medical expenses for you, your spouse, and any dependent children, regardless of whether they're on your health insurance plan. You just need to submit receipts showing the expense and the person it was for.

Do I have to use my FSA debit card, or can I always submit receipts instead?

You can choose either method. Some people prefer the debit card for convenience; others prefer to pay out of pocket and submit receipts to keep better control of their spending. Both methods are valid, and most administrators support both.