How a Flexible Spending Account Works: The Money Flow and the Rules

A Flexible Spending Account lets you set aside pretax money for medical or dependent care costs, then spend it during the year

A Flexible Spending Account (FSA) is an employer-sponsored plan where you contribute a portion of your paycheck before taxes are taken out. Your employer holds that money in an account, and you withdraw it to pay for may be able to access medical expenses or dependent care costs. The tax savings come from never paying federal income tax or Social Security tax on the money you contribute — but the tradeoff is that money left unspent at year's end is forfeited.

The account itself does not invest or grow your money. It sits there until you submit a claim. Your employer or the plan administrator processes the claim, verifies it covers an may be able to access expense, and either reimburses you or pays the provider directly. The entire cycle — from paycheck deduction to reimbursement — typically takes two to four weeks.

Key Takeaways

• You choose how much to contribute each year during open enrollment, and that amount is deducted from your paycheck in equal installments before taxes.
• You can only withdraw money for expenses that meet the IRS definition of may be able to access medical care or dependent care, and you must have a receipt or explanation of benefits to prove it.
• Money left in your account at the end of the plan year is forfeited — there is no rollover to the next year, though some plans offer a short grace period to spend remaining funds.
• You access the money by submitting a claim to your plan administrator with documentation, or by using a debit card if your plan offers one.
• Contribution limits are set by the IRS and change annually; for 2024, the medical FSA limit is $3,200 and the dependent care FSA limit is $5,000 per household.

How money moves from your paycheck into the account

During your employer's open enrollment period — usually once a year in the fall — you decide how much to contribute to your FSA for the coming plan year. You complete a form through your benefits portal or HR department stating a dollar amount. That amount is then divided by the number of pay periods remaining in the plan year, and that portion is deducted from each paycheck before federal income tax, Social Security tax, and Medicare tax are calculated.

If you earn $50,000 a year and contribute $2,400 to a medical FSA, and you are paid biweekly, roughly $92 is deducted from each of your 26 paychecks. Because this happens before taxes, you save approximately 25 to 30 percent on that contribution in federal and payroll taxes — meaning the $2,400 costs you roughly $1,680 out of pocket. Your employer transfers the full $2,400 to the FSA account.

You cannot change your contribution mid-year unless you have a may have access to life event: marriage, divorce, birth or adoption of a child, loss of other health coverage, or a significant change in dependent care costs. A job change or salary increase does not may have access to. If you do not use the money by the end of the plan year, you lose it entirely.

What expenses you can actually pay for with FSA money

The IRS maintains a list of may be able to access medical expenses, and it is narrower than many people expect. may be able to access expenses include copayments, coinsurance, deductibles, and prescription medications. They also include dental work, vision care, hearing aids, and mental health treatment. Insulin and other diabetes supplies are covered. Physical therapy, chiropractic care, and acupuncture count if a doctor prescribes them.

Over-the-counter medications are may be able to access only if you have a prescription from a doctor — taking ibuprofen or allergy medicine without a prescription does not may have access to. Vitamins and supplements are not covered unless prescribed for a specific medical condition. Cosmetic procedures, gym memberships, and general wellness products are not may be able to access. Expenses for a spouse or dependent who is not claimed on your tax return do not may have access to.

For dependent care FSAs, may be able to access expenses are limited to childcare or adult daycare that allows you to work. Tuition for preschool counts only if the primary purpose is childcare while you work, not education. Overnight camp, babysitting for date nights, and school tuition for kindergarten and above do not may have access to. The dependent care FSA has an annual household limit of $5,000 (or $2,500 if married filing separately), separate from the medical FSA limit.

How to access your money and submit claims

There are three ways to spend FSA money. The first is a debit card issued by your plan administrator. You swipe it at the pharmacy, doctor's office, or medical supply store, and the charge is deducted from your account. Not all plans offer debit cards, and some require you to submit a receipt afterward to verify the expense was may be able to access.

The second method is to pay out of pocket and request reimbursement. You submit a claim form to your plan administrator with a receipt, invoice, or explanation of benefits showing the date, amount, and type of expense. The administrator reviews it, confirms it is may be able to access, and sends you a check or direct deposit within one to three weeks. Some plans let you submit claims through a mobile app or website portal.

The third method, available through some employers, is direct payment to the provider. Your doctor's office or pharmacy submits the claim to your FSA on your behalf, and the plan pays them directly. This is common for prescription medications and routine medical visits. You still need to verify the charge is correct and keep your own records.

The "use it or lose it" rule and grace periods

Any money remaining in your FSA account at the end of the plan year is forfeited. You cannot carry it over to the next year, and you cannot get it back as a refund. This is the single biggest drawback of FSAs: if you overestimate your medical expenses, you lose the difference. If you underestimate, you cannot add more money mid-year unless you have a may have access to life event.

Some employers offer a grace period of up to two and a half months after the plan year ends. During this grace period, you can continue to submit claims for expenses incurred during the grace period itself, and the money comes from the previous year's account. Not all plans offer this, and it does not extend the deadline for submitting claims for expenses from the prior year — those must be submitted by the original deadline, usually 60 to 90 days after the plan year ends.

A small number of plans allow a carryover of up to $610 (in 2024) to the next year instead of a grace period. Your employer chooses which option to offer, so check your plan documents to see which applies to you.

How FSAs differ from Health Savings Accounts and other savings options

An FSA and a Health Savings Account (HSA) both use pretax money for medical expenses, but they work very differently. An HSA is only available if you have a high-deductible health plan, and the money rolls over year to year — you never lose it. An FSA has no health plan requirement and higher annual contribution limits, but the money expires at year's end. An HSA can be invested to grow over time; an FSA cannot.

A Dependent Care FSA is separate from a medical FSA. You can contribute to both in the same year, up to the separate limits for each. A Dependent Care FSA is the only way to get a tax break on childcare costs; there is no dependent care HSA.

If your employer does not offer an FSA, you cannot open one on your own. FSAs are employer-sponsored only. If you are self-employed, you cannot use an FSA, but you may be able to use an HSA or claim a dependent care tax credit on your tax return.

Common mistakes to avoid when using an FSA

The most common mistake is contributing too much and losing money at year's end. Estimate conservatively: add up what you actually spent on may be able to access expenses in the past two years, then round down slightly. If you are unsure whether an expense qualifies, ask your plan administrator before you spend the money, not after.

A second mistake is submitting claims without documentation. Your plan administrator will reject a claim if you do not include a receipt, invoice, or explanation of benefits. Keep all receipts and statements for at least three years in case of an audit. Do not assume the provider will submit the claim for you — follow up to confirm it was received and processed.

A third mistake is forgetting the claim deadline. Most plans require you to submit claims for prior-year expenses within 60 to 90 days after the plan year ends. After that deadline passes, the money is gone and you cannot recover it. Mark the deadline on your calendar and submit claims early.

Frequently Asked Questions

Can I use my FSA debit card at any pharmacy or doctor's office?

Most pharmacies and medical providers accept FSA debit cards, but not all do. Some smaller practices or specialty providers may not be set up to process them. If a provider declines the card, you can pay out of pocket and submit a claim for reimbursement instead. Always keep your receipt as backup documentation.

What happens to my FSA money if I leave my job?

You lose access to any money remaining in your FSA account when you leave your employer. You have a limited window — usually 60 to 90 days — to submit claims for expenses you incurred while employed. After that, the remaining balance is forfeited. If you move to a new job with an FSA, you start fresh with a new account and new contribution limits.

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

Only if your spouse is claimed as a dependent on your tax return. If your spouse files taxes separately or is not your dependent, their expenses do not may have access to. Expenses for children you claim as dependents do may have access to, regardless of custody arrangements.

Do I need a prescription for over-the-counter pain relievers to use my FSA?

Yes. As of 2020, over-the-counter medications require a prescription from a doctor to be FSA-may be able to access. This includes ibuprofen, acetaminophen, allergy medicine, and cold medicine. Insulin is the only over-the-counter medication that qualifies without a prescription.

Can I contribute to both a medical FSA and a dependent care FSA in the same year?

Yes. These are two separate accounts with separate contribution limits. You can contribute up to $3,200 to a medical FSA and up to $5,000 to a dependent care FSA (or $2,500 if married filing separately) in the same plan year. The money in each account is tracked separately and has its own deadline for claims.