A Flexible Spending Account makes sense if you have predictable medical costs and want to pay them with pre-tax dollars

An FSA is worth opening if you know you will spend money on medical care, dental work, vision care, or over-the-counter health items in the next year, and you want to reduce your taxable income while doing it. The core trade-off is straightforward: you set aside money before taxes are taken out, which lowers what you owe the IRS, but you must use that money or lose it by the end of the plan year. If you cannot predict your medical spending or you have irregular health costs, an FSA creates risk that is not worth the tax savings.

The decision hinges on three questions: Do you have medical expenses coming? Can you estimate them fairly closely? And can you spend the money before the year ends? If you answer yes to all three, an FSA usually saves you money. If you answer no to any of them, a regular savings account or your health insurance deductible may serve you better.

Key Takeaways

  • An FSA reduces your taxable income by letting you pay medical expenses with pre-tax dollars, which typically saves you 20 to 40 percent on those costs depending on your tax bracket.
  • You must use the money in your FSA by the end of the plan year or lose it, so you need to estimate your medical spending accurately before you enroll.
  • FSAs cover a specific list of items: copays, deductibles, prescriptions, dental work, vision care, hearing aids, and many over-the-counter health products, but not health insurance premiums or cosmetic procedures.
  • You can only open or change your FSA election during your employer's open enrollment period, which is usually once a year in the fall, or within 30 to 60 days of a major life event like marriage or a new job.
  • If you have a Health Savings Account available through a high-deductible health plan, you may want to compare the two, because an HSA lets you roll unused money forward while an FSA does not.

How much money you actually save with an FSA

The tax savings depend on your income and tax bracket. If you earn $60,000 a year and set aside $2,500 in an FSA, you reduce your taxable income to $57,500. At a federal tax rate of 22 percent, you save $550 in federal taxes alone. Add state and local income tax (which varies by where you live) and Social Security and Medicare taxes, and your total savings often reaches 25 to 40 percent of the money you set aside.

That means a $2,500 FSA contribution might cost you only $1,500 to $1,875 out of pocket, because the other $625 to $1,000 comes from taxes you would have paid anyway. This is not a rebate or a refund — it is straightforward paying for medical expenses with money the government would have taken as tax. The catch is that you must actually spend the $2,500 on covered medical items, or you forfeit the unused portion.

When an FSA is the wrong choice

An FSA becomes a liability if your medical spending is unpredictable or if you cannot estimate it within a few hundred dollars. If you set aside $2,500 but only spend $1,200, you lose $1,300. That wipes out the tax savings and costs you money. People with chronic conditions that require regular prescriptions and copays, or those planning a specific procedure like dental work or vision correction, can estimate spending accurately. People with occasional doctor visits, no regular prescriptions, and no planned procedures cannot.

You should also avoid an FSA if you are likely to change jobs or lose your job during the year. When you leave an employer, your FSA ends, and you lose any unspent money. If you are uncertain about your employment stability, the risk of forfeiture outweighs the tax savings. Similarly, if you have a Health Savings Account available through a high-deductible health plan, compare the two first — an HSA lets you roll unused money forward indefinitely, while an FSA does not.

What expenses an FSA actually covers

FSAs cover copays, coinsurance, and deductibles for any health care service. They cover prescription medications and insulin. They cover dental work, including cleanings, fillings, root canals, and orthodontia. They cover vision care: eye exams, glasses, contact lenses, and laser eye surgery. They cover hearing aids and hearing aid batteries. They cover over-the-counter items with a doctor's letter: pain relievers, allergy medicine, antacids, cold medicine, and first-aid supplies.

FSAs do not cover health insurance premiums, cosmetic procedures, or vitamins and supplements (unless prescribed by a doctor for a specific condition). They do not cover gym memberships or weight-loss programs, even if medically recommended. They do not cover travel to receive medical care or lodging during treatment. The IRS publishes a full list of covered and non-covered items on its website, and your employer's FSA plan document will specify which items their plan covers, because employers can be more restrictive than the IRS allows.

How to estimate your FSA contribution accurately

Start by listing every medical expense you paid in the past year: copays, prescriptions, dental cleanings, eye exams, contact lenses, over-the-counter medications you bought regularly. Add up the total. Then look ahead to the coming year and ask whether that spending will change. If you are planning a procedure like a root canal or LASIK surgery, add that cost. If you are starting a new prescription, add the annual cost. If you are stopping a medication or moving to a lower-copay plan, subtract that.

The result is your estimate. Most people contribute between $1,000 and $3,000 per year, but your number depends entirely on your health and your plan. Be conservative: it is better to contribute less and not use all of it than to contribute more and lose money. You can also ask your employer's benefits administrator for a worksheet or calculator — many provide one during open enrollment. If you are unsure, start with a lower amount and increase it next year once you see how much you actually spend.

The timing and enrollment rules you need to know

You can only open an FSA or change how much you contribute during your employer's open enrollment period, which typically happens once a year in the fall and lasts one to three weeks. If you miss that window, you cannot change your election until the next open enrollment — unless you have a may have access to life event. A may have access to event includes marriage, divorce, birth or adoption of a child, loss of other health coverage, a significant change in your spouse's benefits, or a change in your employment status.

When a may have access to event occurs, you usually have 30 to 60 days to make changes to your FSA election. Your employer's human resources or benefits department will tell you the exact important date. If you do not act within that window, you are locked into your current election for the rest of the year. The FSA plan year itself usually runs from January 1 to December 31, though some employers use a different fiscal year — check your plan documents to know when your year ends and when you must spend remaining money.

FSA versus Health Savings Account: which one to choose

If your employer offers both an FSA and a Health Savings Account (HSA) through a high-deductible health plan, compare them before you decide. An HSA lets you roll unused money forward year after year, building a balance that grows tax-free. An FSA requires you to spend the money each year or lose it. An HSA is portable — if you change jobs, the money stays with you. An FSA ends when you leave your employer.

An HSA also has lower contribution limits than an FSA. For 2024, the HSA limit is $4,150 for individual coverage and $8,300 for family coverage (these amounts change yearly). An FSA limit is set by your employer but is typically $3,200 per year. If you have high medical spending, an FSA lets you set aside more money. If you have moderate spending and want to build long-term savings for future medical costs, an HSA is usually the better choice. If your employer offers both, you cannot contribute to both in the same year — you must choose one.

Common mistakes people make with FSAs

The biggest mistake is overestimating spending. People set aside $3,000 thinking they will use it all, then spend only $1,800 and forfeit $1,200. To avoid this, use your actual spending from the past year as your baseline and adjust only for known changes. Do not guess or round up.

The second mistake is forgetting that FSA money must be spent by a important date. Most plans give you until March 15 of the following year to submit receipts for expenses incurred in the prior year, but some have shorter important date. Mark your calendar and keep receipts. If you do not submit them in time, the money is gone.

The third mistake is not knowing what is covered. People buy items they think are medical — like vitamins, sunscreen, or a fitness tracker — and then cannot use their FSA to pay for them. Before you buy anything with the intention of paying from your FSA, check your plan's list of covered items or ask your benefits administrator. Over-the-counter items especially have strict rules.

Frequently Asked Questions

What happens to my FSA money if I do not use it by the end of the year?

You lose it. The money does not roll over to the next year, and your employer does not refund it to you. Some plans offer a grace period of up to two and a half months into the next year to spend prior-year money, but this is optional and not all employers offer it. Check your plan documents to see if your employer provides a grace period.

Can I use my FSA to pay for my spouse's or child's medical expenses?

Yes, as long as they are covered under your health insurance plan or you claim them as dependents on your tax return. You can use your FSA for any family member's covered medical expenses, not just your own. The money does not have to be in their name — it is your account.

What if I leave my job mid-year — do I lose my FSA balance?

Yes. When you leave your employer, your FSA ends when ready, and you forfeit any unspent balance. You cannot take the money with you or transfer it to a new employer's FSA. This is one reason to be cautious about contributing too much if your job security is uncertain.

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

It depends on the medication and your plan. As of 2020, you can use an FSA to buy over-the-counter pain relievers, allergy medicine, antacids, and cold medicine without a doctor's prescription. However, some employers restrict this, so check your plan. For other over-the-counter items like vitamins or supplements, you typically need a doctor's letter stating the item is medically necessary.

Is it better to open an FSA or just save the money myself?

An FSA is better if you are certain you will spend the money and you want the tax savings. If you set aside $2,500 in an FSA and spend it all, you save 25 to 40 percent in taxes — that is real money. But if you are unsure whether you will spend it, a regular savings account is safer because you keep the money if you do not use it. The tax savings are only worth it if you are confident in your spending estimate.