What Is a Health FSA Account and How Does It Work?

A health FSA account is an employer-sponsored benefit that lets you set aside pre-tax money from your paycheck to pay for out-of-pocket medical, dental, and vision expenses. You pick a contribution amount during open enrollment, that money comes out of your paychecks before federal income tax and FICA are calculated, and you spend it on qualified healthcare costs throughout the plan year. For 2026, the IRS caps your contribution at $3,400.¹

The account is set up under a Section 125 cafeteria plan, the part of the tax code that lets employers offer employees a choice between taxable salary and certain tax-free benefits.² Your employer holds the funds and either issues you a debit card linked to the account or reimburses you after you submit receipts. You don’t own the account the way you own a bank account; your employer sponsors it and sets its terms within IRS rules.

How Much You Can Contribute and What You Save

The $3,400 limit for 2026 applies per employee, not per household. If you and your spouse both have access to a health FSA through separate employers, each of you can contribute up to the full amount.

The tax savings come from two directions. Your contributions avoid federal income tax, which lowers your taxable income for the year. They also avoid the 7.65% FICA tax that combines the 6.2% Social Security tax and the 1.45% Medicare tax.³ On a $3,400 contribution, the FICA savings alone come to roughly $260, on top of whatever you save in income tax.

Some employers contribute money of their own to employees’ health FSAs. Those employer dollars count toward the same $3,400 cap. If your employer puts in $500, you can contribute up to $2,900 of your own salary.

Your Full Election Is Available on Day One

The full amount you elected for the year is available on the first day of the plan year, even after only one paycheck deduction. If you elect $3,400 for 2026 and have a $3,400 medical bill in January, you can use the entire balance immediately.⁴ This is the uniform coverage rule. Your employer fronts the money and recoups it through your remaining payroll deductions.

The rule also runs in your favor if you leave the company. If you spent your full election early in the year and then quit, your employer generally cannot recover the difference between what you spent and what you contributed through payroll.

What You Can Spend the Money On

Health FSA funds cover qualified medical expenses as defined by the IRS in Publication 502.⁵ That list is broad. Doctor visit copays, lab work, prescription drugs, dental cleanings, fillings, crowns, eye exams, glasses, contact lenses, and physical therapy all qualify. Since the CARES Act took effect in 2020, over-the-counter medications and menstrual care products qualify without a prescription.⁶

Most plans issue a debit card that you can swipe at the pharmacy or doctor’s office. If you pay out of pocket, you submit an itemized receipt or an Explanation of Benefits from your insurer to the plan administrator. Keep documentation even when you use the card, because administrators sometimes request verification after the fact and can require you to pay the money back if you can’t produce it. Most plans include a run-out period, commonly 90 days after the plan year ends, for submitting receipts on expenses you incurred during that plan year.

Expenses That Don’t Qualify

The IRS separates treating a specific medical condition from generally improving your health, and the second category is out.⁵ Commonly denied items include:

Gym memberships and fitness classes, even when a doctor recommends exercise.
Cosmetic procedures such as face lifts, hair transplants, teeth whitening, and liposuction, unless they address a congenital abnormality, injury, or disfiguring disease.
Vitamins and general nutritional supplements, unless a physician prescribes them for a specific diagnosed condition.
Childcare and babysitting, even when needed so you can attend a medical appointment.
Cannabis products, regardless of state legality, because the substance remains federally controlled.

The working test: if the expense primarily treats or prevents a specific medical condition, it likely qualifies. If it just makes you feel better in a general sense, it likely doesn’t.

Enrolling and Changing Your Election

You can enroll only if your employer offers a Section 125 cafeteria plan. Self-employed people aren’t eligible. Enrollment happens during your employer’s annual open enrollment period, and the election you make stays locked for the full plan year.

Mid-year changes require a qualifying life event: marriage or divorce, birth or adoption of a child, loss of other health coverage, or a spouse’s change in employment status. You typically have 30 to 60 days from the date of the event to notify your employer and adjust your election.⁷ Miss that window and your original election stands until the next open enrollment.

The Use-It-or-Lose-It Deadline

Money left in the account at the end of the plan year is generally forfeited. This is the single biggest drawback of a health FSA. The IRS lets employers offer one of two relief options, but not both, and neither is required:

Carryover. The plan lets you roll a portion of your unused balance into the next plan year. For the 2025-to-2026 transition, the maximum carryover is $680. Anything above that is still forfeited.⁸
Grace period. The plan gives you up to two and a half extra months after the plan year ends to incur new expenses against last year’s balance. For a calendar-year plan, that typically means a March 15 deadline. Anything unspent after the grace period is forfeited.⁴

If your employer offers neither, the deadline is the last day of the plan year. Forfeited money stays with the employer to offset plan administrative costs, and it cannot be refunded to you.⁴ The practical response is to estimate conservatively. Contributing slightly less than you think you’ll need beats forfeiting hundreds of dollars in December.

What Happens When You Leave the Job

Coverage usually ends on your termination date. You can be reimbursed only for expenses incurred before that date, and any remaining balance is typically forfeited.⁹ This is where people lose real money. You might have $1,500 in the account when you give notice and walk away from it.

One possible lifeline: if your employer is subject to COBRA and your account is “underspent” (you’ve contributed more than you’ve been reimbursed), you may be offered COBRA continuation for the health FSA. Electing it lets you keep submitting claims for expenses incurred after your termination date, but you’ll pay the full contribution amount plus a 2% administrative fee with after-tax dollars. COBRA on a health FSA typically only lasts through the end of the plan year in which you left, not the 18 months that applies to group health insurance.

Health FSA and HSA at the Same Time

If you’re covered by a general-purpose health FSA that reimburses all qualified medical expenses, you cannot contribute to a health savings account during the same period.⁴ A limited-purpose FSA, which restricts reimbursement to dental and vision expenses only, preserves your HSA eligibility.¹⁰ If you’re enrolled in a high-deductible health plan and want both accounts, the limited-purpose FSA is the way to make it work.

One timing trap: if your general-purpose health FSA has a grace period that overlaps with the start of a new plan year, you’re disqualified from HSA contributions during that grace period unless your FSA balance was zero at the end of the prior plan year.⁴ Plans with a carryover instead of a grace period can create the same conflict. Check with your benefits administrator before assuming the switch is clean.

A Note on the Dependent Care FSA

A dependent care FSA is a separate account with different rules. It pays for childcare or elder care expenses that let you work, such as daycare, after-school programs, or home care for a qualifying adult dependent. It does not cover medical expenses, and a health FSA does not cover childcare. Enrolling in one has no effect on your ability to enroll in the other.

1
FSAFEDS. New 2026 Maximum Limit Updates
2
Office of the Law Revision Counsel. 26 USC 125 – Cafeteria Plans
3
Internal Revenue Service. Topic No. 751, Social Security and Medicare Withholding Rates
4
Internal Revenue Service. Publication 969, Health Savings Accounts and Other Tax-Favored Health Plans
5
Internal Revenue Service. Publication 502, Medical and Dental Expenses
6
Internal Revenue Service. IRS Outlines Changes to Health Care Spending Available Under CARES Act
7
U.S. Office of Personnel Management. When Must I Report a Qualifying Life Event
8
Proskauer Rose LLP. IRS Releases Annual Increases to Health FSA and Transportation Fringe Benefit Limits for 2026
9
U.S. Department of Labor. FAQs on COBRA Continuation Health Coverage for Workers
10
FSAFEDS. Eligible Limited Expense Health Care FSA Expenses