What Is an FSA?
A Flexible Spending Account, or FSA, works like a health-spending allowance you build out of your own paycheck: you pick an amount for the year, it skips taxes on the way out, and you spend it on care during the plan year through your employer's benefits program. The pre-tax part is the entire trick: the money comes out of your check before taxes are calculated, so care you were already going to pay for gets cheaper. Quick disambiguation, because the acronym is crowded: "FSA" also stands for Federal Student Aid, the Farm Service Agency, and an actuarial credential. This page is about the health benefits account, the one people mention in the same breath as its cousin, the Health Savings Account (HSA). Same neighborhood, very different animals.
How an FSA Works
You elect a dollar amount during open enrollment, it comes out of your paycheck before taxes in equal installments across the year, and the entire amount you elected is available to spend on day one of the plan year, before you've actually contributed most of it.
That last part surprises almost everyone. The IRS's uniform coverage rule, spelled out in Publication 969, requires that you "must be able to receive the maximum amount of reimbursement (the amount you have elected to contribute for the year) at any time during the coverage period, regardless of the amount you have actually contributed." In plain English: elect your full amount in November, and if surgery lands in January, the whole election is there waiting, even though only one paycheck's worth has come out so far. It works like an interest-free advance from your own benefits plan.
One string attached: your election generally locks once open enrollment closes. Changing it mid-year takes a qualifying life event, like marriage or a new baby. More on that in the FAQ.
The 2026 FSA Contribution Limit
The 2026 health FSA contribution limit is $3,400 per employee, set annually by the IRS in Revenue Procedure 2025-32. That's the one number this page needs. The full 2026 and 2027 limits for every account type, including the separate dependent care and limited purpose caps, live in our HSA and FSA contribution limits guide.
Is an FSA Worth It?
Yes, if you expect predictable medical or dental costs this year. The tax savings are real and immediate. But say yes with your eyes open: unlike an HSA, FSA money you don't spend doesn't roll over indefinitely, and it doesn't travel with you if you leave your job.
Here's the honest math on the upside. FSA money skips federal income tax and payroll taxes, which works out to savings near 30% for many households on care you were going to buy anyway, depending on your bracket. Braces on the calendar, a prescription you refill monthly, glasses, planned physical therapy: if you can see the expense coming, the FSA makes it cheaper, full stop.
The eyes-open part comes in three flavors. Forfeiture risk: money left at the deadline can be gone for good, and the next section covers exactly how. The guessing game: you commit during open enrollment, before the year happens, and overshooting has a real cost. Job-lock: the account belongs to your employer's plan, not you, so an exit usually strands the balance. Predictable costs and a stable job: enroll. Genuinely unpredictable year: elect only what you're certain to spend, or pass.
What Happens to Unused FSA Money
By default, FSA money you haven't spent by the end of the plan year is forfeited to your employer. That's the famous "use-it-or-lose-it" rule. Most employers soften it with one of two options, but never both at once.
Option one is a carryover. IRS Notice 2013-71 lets plans roll a capped, IRS-indexed slice of unused money into the next plan year. Option two is a grace period. Under IRS Notice 2005-42, a plan can give you up to two and a half extra months after year-end (through March 15 on a calendar-year plan) to spend what's left. A plan cannot offer both; the IRS says it outright: "A plan adopting this carryover provision is not permitted to also provide a grace period with respect to health FSAs." And some plans offer neither, so read your plan documents before you count on either cushion.
Then there's the exit rule nobody flags during enrollment: leave your job, for any reason, and your remaining balance is forfeited to the employer. Notice 2013-71 allows one out, electing COBRA continuation coverage for the FSA so you can keep spending it down. The rule cuts the other way too: if you had already spent more than you contributed by your last day, you keep the care and owe nothing back. That risk sits with the employer, under the same uniform coverage rule from earlier. If a resignation letter and an FSA balance are both in your near future, book the dentist first.
The Three Types of FSAs
There are three kinds of FSA, and picking the wrong one next to an HSA can quietly cost you thousands.
Health FSA. The standard version, and the one this guide has described so far. It covers the full range of qualified medical expenses. The catch: enrolling in a general-purpose health FSA makes you ineligible to contribute to an HSA, because both claim the same tax territory.
Limited-Purpose FSA (LPFSA). Dental and vision only, and the one health-care FSA you can hold alongside an HSA. This is the pairing move most people miss. The full both-accounts playbook lives in our HSA vs FSA guide.
Dependent Care FSA (DCFSA). A completely separate account for care expenses like day care, preschool, summer day camp, and care for a dependent adult, with its own separate annual cap, and no effect on your ability to fund an HSA. It shares the acronym and the use-it-or-lose-it clock with the health FSA, and nothing else; the current caps are in our HSA and FSA contribution limits guide.
Who Can Have an FSA
An FSA is offered through an employer only. There's no version you can open on your own the way you can with an HSA, and self-employed people are out of luck entirely. Publication 969 puts it flatly: "Self-employed persons aren't eligible for FSAs." If your employer doesn't offer one, there's no FSA in your future until that changes.
One thing an FSA does not require: any particular insurance. An HSA demands a high-deductible health plan (HDHP); an FSA pairs with whatever coverage your employer offers, HDHP or not.
Spending It: The FSA Card and Claims
Most FSAs come with a debit card pre-loaded with your election, so eligible purchases are deducted automatically at checkout without you filing anything. At pharmacies and major retailers, an inventory system called IIAS recognizes eligible items on its own and approves them at the register, everyday OTC items like sunscreen included.
When the system can't verify a purchase, or the card gets declined or flagged, your plan administrator will ask for an itemized receipt showing what you bought, when, and for how much. Submit it and the claim clears. For dual-use purchases, items that can be everyday buys or qualified medical expenses depending on why you need them, the document that settles the question is a Letter of Medical Necessity.
What Does an FSA Cover? ("FSA Eligible" and Where to Check)
An FSA covers the same IRS definition of qualified medical expenses as an HSA: doctor visits, prescriptions, dental and vision care, and hundreds of everyday health items, plus dual-use wellness purchases like a gym membership once a Letter of Medical Necessity ties it to a specific health condition.
The master definition sits in IRS Publication 502, which counts as medical expenses "the costs of diagnosis, cure, mitigation, treatment, or prevention of disease." When a product page or a store shelf tag says "FSA eligible," that's the claim being made: this item fits the IRS definition, so your FSA can pay for it, either on its own or with documentation connecting it to your health.
The definition is the start, not the answer. What you actually want is a verdict on the specific thing in your cart, and that's what our per-item guides are for, from fitness trackers to gym memberships. For anything dual-use, our Letter of Medical Necessity guide walks the whole path from condition to reimbursement.
FSA vs. HSA: The One-Paragraph Difference
The short version: an HSA is yours to keep and requires an HDHP; an FSA is employer-owned, available with any health plan, but resets close to zero every year. HSA money rolls over forever, invests like a retirement account, and follows you between jobs. FSA money arrives all at once on day one, which an HSA can't match, but it lives on a timer. If your employer offers both at once, that usually means a health FSA versus HSA choice, or an HSA paired with the limited-purpose type. The full side-by-side, including that LPFSA pairing playbook, is in our HSA vs FSA comparison.
