An FSA saves money only if you will actually spend the money on may be able to access expenses

A Flexible Spending Account is worth it if two things are both true: you have predictable medical or dependent care costs coming up in the next year, and you can afford to set aside that money now without needing it for something else. If either condition fails, an FSA can cost you money instead of saving it.

The math is straightforward. You contribute pre-tax dollars — money that never gets taxed as income — and use it to pay for may be able to access expenses. If you would have paid for those expenses anyway, you save roughly 20 to 40 percent depending on your tax bracket. But if you contribute money and don't spend it by the end of the plan year, you lose it. That risk is the reason FSAs are not right for everyone.

Key Takeaways

  • An FSA saves money only if you spend all the money you contribute before the plan year ends, because unused funds are forfeited.
  • Your tax savings range from roughly 20 to 40 percent of what you contribute, depending on your income tax bracket and whether you pay self-employment tax.
  • An FSA makes sense if you have predictable medical costs like prescriptions, copays, or dental work already scheduled for the coming year.
  • An FSA is risky if your medical needs are unpredictable, your income is unstable, or you might need the cash for emergencies.

When the math actually works in your favor

The FSA advantage appears when you know what you will spend. If you take a prescription that costs $100 per month, you know you will spend $1,200 next year. If you have dental work scheduled, you know the cost. If you have a child in daycare, you know the annual bill. In these cases, contributing that amount to an FSA and paying for it from the account saves you the taxes you would have paid on that income.

A concrete example: suppose you earn $60,000 per year, you are in the 22 percent federal tax bracket, and you pay 7.65 percent in Social Security and Medicare tax. That is a combined 29.65 percent tax rate. If you contribute $2,000 to an FSA for known medical expenses, you save $593 in taxes. You spend the full $2,000 on may be able to access care. Net result: you paid $1,407 for $2,000 in medical expenses instead of $2,000.

The savings grow if your state has income tax. In a state with 5 percent income tax, the same $2,000 contribution saves $713 in taxes. The higher your tax bracket, the larger your savings.

The forfeiture risk that makes FSAs dangerous

The FSA's biggest drawback is the use-it-or-lose-it rule. Money you don't spend by the end of the plan year (usually December 31) is forfeited to your employer. There is no carryover, no refund, no exception. If you contribute $2,500 and spend only $2,000, you lose $500 permanently.

This rule makes FSAs risky for anyone whose medical needs are unpredictable. A year with no major dental work, no new prescriptions, and no unexpected doctor visits can leave you with unused funds. Even a small miscalculation — contributing $2,400 when you only spend $2,000 — erases your tax savings and costs you money.

Some employers offer a grace period (usually 2.5 months into the next year) to spend remaining funds, or a carryover of up to $610 (the amount changes yearly). Check your plan documents to see if yours does. But most plans have neither, so you cannot count on either option.

How to estimate whether you will spend what you contribute

Start by listing every medical and dependent care expense you expect in the next 12 months. Include prescriptions (get the exact cost from your pharmacy), copays for regular doctor visits, dental cleanings and any scheduled work, vision exams and glasses or contacts, and childcare or adult dependent care costs. Add up the total.

Then subtract what you will pay out of pocket anyway. If you have already met your deductible or you know you will meet it, those expenses are already covered. If you have a Health Savings Account (HSA) instead of an FSA, you might use that for some expenses instead. Be honest about what you will actually spend from the FSA.

If the number you arrive at is less than $500, an FSA is probably not worth the risk. The tax savings on a small contribution are modest, and the chance of forfeiting some of it is high. If the number is $1,500 or more and you are confident in it, an FSA likely saves you money.

FSAs versus HSAs: which one makes sense

If your employer offers both an FSA and a Health Savings Account, the HSA is usually the better choice. An HSA lets you carry unused money forward year after year — there is no forfeiture. You get the same tax savings on contributions, and you can invest the money to grow it over time. The tradeoff is that HSAs require a high-deductible health plan, which means you pay more out of pocket for medical care until you hit the deductible.

An FSA makes more sense than an HSA only if you are not may be able to access for an HSA (because you have a low-deductible plan) or if you have very high predictable expenses and want to use the money when ready. If you have a choice between the two and you are unsure, an HSA carries less risk because you do not lose unused money.

Common mistakes that turn FSAs into money losers

The most common mistake is overestimating how much you will spend. People contribute the maximum ($3,300 for 2024, though this amount changes yearly) because they think they might need it, then spend far less. Contributing $3,300 and spending $2,000 means you lose $1,300 — which wipes out your tax savings and costs you money.

Another mistake is contributing to an FSA when your income or job is unstable. If you leave your job mid-year, you usually lose access to your FSA and forfeit any unused balance. If you are thinking about changing jobs, freelancing, or taking unpaid leave, an FSA is risky.

A third mistake is forgetting to submit receipts or losing track of what you have spent. Some FSA administrators require you to submit proof of expense before they reimburse you. If you do not keep receipts or you forget to submit them by the important date, you may not be able to access money you contributed.

Situations where an FSA is clearly not worth it

Do not contribute to an FSA if your medical needs are highly unpredictable. If you rarely see a doctor, have no chronic conditions, and do not take regular prescriptions, you cannot reliably estimate your spending. The risk of forfeiture is too high.

Do not contribute if you are planning to leave your job or change your employment status in the next year. You will lose any unused FSA balance when you leave, and you cannot take it with you.

Do not contribute more than you are confident you will spend. It is better to contribute $1,000 and spend $1,000 than to contribute $2,000 and spend $1,500. The tax savings on $1,000 are real; the loss on $500 is permanent.

Do not use an FSA as a savings account. The money is not yours to keep if you do not spend it. It is a tool for reducing taxes on money you will definitely spend on may be able to access care.

Frequently Asked Questions

Can I change my FSA contribution amount during the year?

Only if you have a may have access to life event: marriage, divorce, birth or adoption of a child, loss of other health coverage, or significant change in dependent care costs. A job change or income change does not usually may have access to. If you cannot change your contribution and you realize you overestimated, you will likely lose the unused money.

What happens to my FSA if I get laid off or quit my job?

You lose access to your FSA when ready and forfeit any unused balance. Some employers allow you to submit claims for expenses you incurred before you left, but only within a short window (usually 60 to 90 days). You cannot carry the money to a new job or convert it to cash.

Can I use my FSA for over-the-counter medications without a prescription?

As of 2020, you can use FSA funds for over-the-counter medications and medical supplies without a prescription from a doctor. This includes pain relievers, allergy medicine, and first aid supplies. Check your plan documents, because some employers have more restrictive rules.

Is it worth contributing a small amount to an FSA just to get some tax savings?

Only if you are very confident you will spend it. Contributing $500 and spending $500 saves you roughly $150 in taxes (depending on your bracket). But contributing $500 and spending $300 costs you $200 in forfeited money, which erases your savings and leaves you worse off. The smaller the contribution, the higher the risk.

What if I have a spouse with an FSA — can we coordinate to avoid forfeiture?

You can each have your own FSA through your respective employers, and you can coordinate your contributions to cover your household's expected expenses. But each account has its own forfeiture rule. If one spouse's account has unused money, that money is still lost, even if the other spouse's account is depleted.