Flexible Spending Account (FSA)

A flexible spending account is a benefit offered through an employer's cafeteria plan under section 125 of the Internal Revenue Code. The employee elects an annual amount before the plan year begins, that amount is deducted from pay before federal income tax and payroll taxes, and the plan reimburses qualifying expenses as they are incurred. For a health flexible spending account the employee's own salary-reduction contributions are capped by section 125(i), currently $3,400.

The naming is genuinely split between two federal agencies, and both are correct. The IRS writes health flexible spending arrangement, in Revenue Procedure 2025-32 and throughout Publication 969. HealthCare.gov titles its own entry Flexible Spending Account and notes on the same page that these "are sometimes called Flexible Spending Arrangements." Unlike some account-versus-arrangement disputes in tax law, neither term here describes a narrower thing than the other; the two bodies simply settled on different words for the same benefit. Plan documents tend to follow the IRS and everyday speech follows CMS.

🔑 Uniform coverage is the feature that makes the arrangement worth having. The rule is that "the maximum amount of reimbursement from a health FSA must be available at all times during the period of coverage", reduced only by reimbursements already made for that period. It comes from the proposed regulations issued under section 125 in 2007, which have never been finalised; Treasury stated in the same document that taxpayers may rely on them pending final regulations, and plans follow them. So the entire annual election is available from the first day of the plan year, regardless of how little has been withheld so far. An employee who elects $2,000 and needs $2,000 of dental work in January can claim the full amount, and if they leave the employer in February the employer generally absorbs the difference rather than recovering it. The risk therefore runs in the employee's favour, which is the reverse of nearly every other pre-tax benefit and the reason the forfeiture rule exists as a counterweight. Note that the rule is written for health flexible spending accounts specifically: a dependent care arrangement reimburses only what has actually been contributed.

🔴 The election is locked harder than any other cafeteria-plan choice, and most explanations understate it. Treasury Regulation section 1.125-4(a) states two things that have to be read together: a plan "may permit an employee to revoke an election during a period of coverage and to make a new election only as provided" in the listed circumstances, and "section 125 does not require a cafeteria plan to permit any of these changes." So a permitted event is necessary and not sufficient, and the plan document has the last word. Beyond that, section 1.125-4(f)(1) provides that the significant cost or coverage change route "does not apply to an election change with respect to a health FSA." That route is what lets employees adjust other cafeteria benefits when their price or availability shifts mid-year, and it is closed to the health flexible spending account entirely. What remains are the change in status events, such as marriage, divorce, a birth or adoption, or a change in employment status, and even those must satisfy a consistency rule requiring the change to correspond with the event.

Forfeiture, and the two reliefs that are mutually exclusive. Money not spent by the end of the plan year is forfeited to the employer. An employer may soften that in one of two ways: a carryover of up to $680 of unused amounts into the next plan year, or a grace period of up to two and a half months after the plan year in which to incur further expenses. Publication 969 states the constraint plainly: a plan adopting a carryover provision is not permitted also to provide a grace period for health flexible spending accounts. A plan may offer one, or the other, or neither, and which applies is a question about your employer rather than about the law.

It is not an account and it is not yours. Despite the name, no separate account holds the money and nothing is invested; the arrangement is a promise by the employer to reimburse. It does not move with you between jobs, it cannot be carried into retirement, and Publication 969 states that self-employed persons are not eligible for one at all. That is the sharpest contrast with a health savings account, which Publication 969 calls "portable" and whose contributions "remain in your account until you use them." The two arrangements look similar on a benefits enrolment screen and behave nothing alike.

🔴 A general-purpose health flexible spending account disqualifies health savings account contributions. The reason is in the eligibility test at Internal Revenue Code section 223(c)(1)(A): you must not be covered by another health plan that fails the high deductible test and covers a benefit your qualifying plan covers. A general-purpose arrangement reimburses exactly those expenses, so it counts. A limited-purpose version, confined to categories such as dental and vision, does not, and neither does a post-deductible design. A spouse's general-purpose account can disqualify you as well, if it is able to reimburse your expenses, which is the version households most often miss.

The dependent care version is a different provision with different rules. It sits under section 129 rather than section 125(i), reimburses employment-related care rather than medical expenses, and its exclusion limit is a flat statutory $7,500, or $3,750 for a married person filing separately. That figure was raised from $5,000 for tax years beginning after 2025 and, unlike the health limit, it carries no inflation adjustment, so it will stay where it is until Congress moves it again.

1. You elect an annual amount before the plan year begins, during the employer's open enrollment window.

2. The amount is divided across your paychecks and withheld before federal income tax and payroll taxes, which is where the saving comes from.

3. The full annual election is available immediately for a health flexible spending account, so a claim in the first week can exceed everything withheld to date.

4. You submit eligible expenses and are reimbursed, or pay directly with a plan debit card if the employer provides one.

5. The election stands for the year unless a permitted change event occurs and the plan chooses to allow the change.

6. At year end the balance is forfeited, unless the plan offers a carryover or a grace period.

A hypothetical, showing the uniform coverage rule and its cost to the employer. Ravi elects $2,400 for the coming plan year. He is paid twice a month, so 2,400 ÷ 24 = $100 comes out of each paycheck before tax. In the second week of January he needs $2,400 of dental work. He has contributed nothing yet, and the plan reimburses the full $2,400 anyway, because the whole election must be available from the start of the plan year.

Now suppose he leaves the employer at the end of March, having contributed five paychecks' worth: 5 × 100 = $500. The employer generally absorbs the remaining 2,400 − 500 = $1,900. The risk does not run the other way, and no repayment is owed. Figures are illustrative; the mechanism is the reason employers set an election ceiling and the reason the forfeiture rule exists alongside it.

The same year, the other direction. Suppose instead Ravi elects $2,400 and spends only $900, and his plan offers a carryover rather than a grace period. He carries forward up to the carryover limit and forfeits the rest. Had his employer offered a grace period instead, he would have had until mid-March of the following year to incur further eligible expenses, but no carryover at all. His employer cannot offer both.

Pros

• Contributions escape federal income tax and payroll taxes, so the saving is larger than an income-tax deduction of the same size.
• The full annual election is available from day one on a health flexible spending account, which turns it into interest-free financing for a known expense early in the year.
• It works alongside any employer health plan, including plans that are not HSA-eligible, so it is available to people the health savings account rules exclude.
• The eligible-expense list is broad and includes many items the health plan itself does not cover.

Cons

• Unspent money is forfeited, and the relief options are capped and mutually exclusive.
• The election is locked for the year, and the route that lets employees adjust other cafeteria benefits for cost or coverage changes does not reach a health flexible spending account at all.
• It is not portable. Leaving the employer generally ends access to the balance, subject to whatever continuation the plan provides.
• It disqualifies health savings account contributions unless it is a limited-purpose version, and a spouse's account can do the same to you.
• Self-employed people cannot use one.
• Estimating a year of medical spending in advance is genuinely difficult, and the penalty for guessing high is losing the money.