The Short Answer
A flexible spending account (FSA) is an employer-offered benefit that lets you set aside pre-tax money from your paycheck to pay for qualified medical or dependent care expenses. Because the money goes in before taxes are taken out, it lowers your taxable income and stretches those dollars further. The catch is the “use it or lose it” rule: funds generally must be spent within the plan year or a short grace period, or they’re forfeited.
In short, an FSA is a pre-tax spending account for expected health or care costs that usually has to be used within the year.
How an FSA Works
- You decide during open enrollment how much to contribute for the year, up to an annual limit set by the IRS.
- The amount is deducted from your paychecks in equal pre-tax installments over the year, lowering your taxable income.
- You pay for qualified expenses — copays, prescriptions, and many other health costs — using the FSA, often with a linked debit card.
- Unused funds are generally forfeited at year-end, though some plans offer a short grace period or a small carryover.
FSA vs. HSA
- FSA — offered through an employer, funds generally don’t roll over year to year, and the account isn’t yours if you leave the job. Available with most plan types.
- HSA — available only with a high-deductible health plan, funds roll over indefinitely, and the account stays with you when you change jobs.
A Simple Example
Example: An employee expects about $1,200 in copays, prescriptions, and dental work next year and elects to put $1,200 into a health FSA. That $1,200 is deducted pre-tax across the year, so if they’re in a combined 25% tax bracket, they effectively save about $300 compared to paying those bills with after-tax dollars. The key is estimating carefully — if they only spend $900, the remaining $300 could be forfeited under the use-it-or-lose-it rule.
Types of FSAs and Key Rules
- Health care FSA — covers medical, dental, and vision costs not paid by insurance, like copays, prescriptions, and eyeglasses.
- Dependent care FSA — covers eligible child or dependent care costs, such as daycare, so you can work; it has its own separate contribution limit.
- The full health FSA amount is available on day one, even though you fund it gradually through payroll deductions across the year.
- Estimate conservatively, since over-contributing risks forfeiting money, while under-contributing simply means paying some costs with regular after-tax dollars.
The Bottom Line
An FSA is a pre-tax way to pay for predictable health or dependent care costs, lowering your taxable income in the process. Its main limitation is the use-it-or-lose-it rule, which makes accurate estimating important. For people who can reliably predict at least some yearly medical or care spending, an FSA is a straightforward way to make those dollars go further.
Frequently Asked Questions
What is an FSA in simple terms?
It’s an account offered by employers that lets you set aside money from your paycheck before taxes to pay for medical or dependent care costs, lowering your taxable income.
What does “use it or lose it” mean for an FSA?
Money left in a health FSA at the end of the plan year is generally forfeited. Some plans soften this with a short grace period to spend leftover funds or a small carryover to the next year, but you shouldn’t assume that without checking your plan.
Can I have both an FSA and an HSA?
Generally not a standard health FSA and an HSA at the same time, because a general FSA disqualifies you from HSA contributions. A “limited-purpose” FSA (dental and vision only) can sometimes be paired with an HSA — your plan documents will spell out what’s allowed.
What can I buy with a health FSA?
Qualified medical expenses like copays, deductibles, prescriptions, eyeglasses, dental care, and many over-the-counter items. The IRS defines what qualifies, and your plan administrator can confirm specific purchases.
What happens to my FSA if I leave my job?
A health FSA generally doesn’t move with you, since it’s tied to your employer. You typically can only be reimbursed for expenses incurred before you left, though COBRA continuation is sometimes an option for a health FSA.
How much can I contribute to an FSA?
The IRS sets an annual limit for health FSAs that can change each year, and dependent care FSAs have a separate limit. Your employer may set a lower cap, so check your plan’s specifics during open enrollment.
This article is for educational purposes only and is not insurance, financial, tax, or legal advice. Coverage terms, costs, eligibility, and rules vary by insurer, plan, and location, and change over time. Read your own policy documents and consult a licensed insurance agent or qualified professional before making decisions about your coverage.