How to Choose the Right Amount for Your FSA

First, determine if your employer lets you carry over a portion of unused funds, or allows a grace period to spend the cash.
Lacie Glover
By Lacie Glover 
Edited by Brad Walters

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If you’re among the millions who get health insurance and other benefits from an employer, fall is open enrollment time. Among your important choices may be deciding on contributing to a flexible spending account, or FSA, and how much money you want to contribute to it.

What is a flexible spending account?

FSAs are offered by some employers as a part of a benefits package. They have some specific rules set by the IRS:

  • You can spend FSA money only on “qualified medical expenses,” as determined by the IRS.

  • The money in an FSA comes out of your paycheck before taxes, in regular increments. FSAs are generally pre-funded, meaning the full contribution is available to spend at the beginning of the year. If you leave your company mid-year, you will likely have to pay back spent funds that haven't been covered by your paycheck deductions yet.

  • The rule for the money is “use or lose,” meaning you lose any amount you haven't spent at the end of the year. That's unlike a health savings account, or HSA, where the money you add is yours forever.

Spend your FSA money by the deadline

“The No. 1 thing you should know about your FSA is what the deadline is,” says Ijeoma Iruke, consumer education specialist at “We work really hard, contribute these funds, get the tax benefits — it’s a total bummer if you set this money aside and you’re not able to use it.”

However, the IRS rules make the FSA use-or-lose-it deadline flexible. That generally plays out in two ways. Ask your benefits administrator whether your employer offers either of these options before deciding on your final contribution for the next year:

  • Many employers let you carry over as much as $500 in unused funds for up to a year.

  • Other employers might offer a grace period, in which you can spend the unused money in the first 2½ months of the next plan year.

Who do you "lose it” to? Any leftover money goes back to the owner of the FSA plan, most likely your employer, “to offset administrative expenses,” says Jody Dietel, chief compliance officer at WageWorks, a company that provides benefits on behalf of employers.

Determining your FSA amount

The FSA contribution limit in 2018 will be $2,650, which comes out to about $221 per month.

If your medical expenses are straightforward, here are two easy rules of thumb for choosing an FSA amount:

  • If your out-of-pocket medical bills typically amount to $221 a month or more — or roughly $2,650 a year — consider contributing the maximum to your FSA.

  • If your medical expenses are generally low, contributing the total of your approximate copays, dental and vision expenses for next year is probably enough.

Medical costs can be hard to predict. You can use this year’s expenses to predict next year’s with the help of this calculator.

Adding in some wiggle room: It’s helpful to have your health plan’s deductible amount set aside for an emergency if you can afford it. The average health insurance deductible in employer plans was $1,505 for an individual in 2017, according to the Kaiser Family Foundation.

If you can’t afford to add that amount to your FSA amount, consider adding a little more than the total of what your calculation of costs showed.

Iruke adds $200 to $300 for the year to her own FSA in case of an emergency. “If you have some left over, you might be surprised at what you can get with it,” she says.

What to do with extra cash in your FSA

If you have unspent FSA money as the year is winding down, here’s what you can do:

  • If your FSA has the carryover option, subtract the leftover amount from next year’s contribution.

  • If your FSA has a grace period into 2018, schedule any medical visits you can during that time and use your surplus to start paying down your 2018 health insurance deductible.

  • Make sure you’re using FSA money for everything you can. Dental and vision costs are eligible, including expensive treatments such as braces and Lasik vision surgery.

  • Spend the leftover money on things that you can use throughout 2018. All items at are eligible. Product examples include thermometers, blood pressure monitors and sunscreen with a sun protection factor, or SPF, of 30 or higher. You can’t use FSA money for over-the-counter drugs such as Tylenol unless you have a prescription for it from your doctor.

One last reminder: Many FSAs provide debit cards to pay for expenses, but save your receipts in case a charge is rejected and you need to prove your expense.