FSA Use-It-or-Lose-It Rule Explained

The FSA use-it-or-lose-it rule is a foundational constraint governing flexible spending accounts, requiring that funds not spent or obligated by a plan-year deadline are forfeited to the employer. This rule applies to health care FSAs and dependent care FSAs operating under Internal Revenue Code Section 125. Understanding its mechanics, the limited relief options available, and the decision points around annual contribution elections directly affects how much pre-tax money an account holder retains.

Definition and Scope

The use-it-or-lose-it rule originates from IRS regulations under IRC § 125, which govern cafeteria plans. Under these regulations, a health FSA must meet the "uniform coverage" rule — meaning the full annual election amount is available on day one of the plan year — and as a structural counterpart, funds remaining at year-end that are not covered by an employer-authorized extension must be forfeited. The employer, not the employee, retains any forfeited balances.

This rule distinguishes FSAs sharply from Health Savings Accounts (HSAs), where unused balances roll over indefinitely without any forfeiture requirement. A direct comparison of these account types is available at HSA vs. FSA vs. HRA Overview and Comparison. Health Reimbursement Arrangements (HRAs) also follow different carryover standards set by employer plan design, covered under the broader regulatory context for health savings.

The rule applies nationally to all FSAs offered through employer-sponsored cafeteria plans. It does not apply to HSAs, and its application to HRAs is governed by separate employer-design rules rather than § 125 directly.

How It Works

The standard operating sequence of the use-it-or-lose-it rule follows a predictable structure:

Election: The employee elects a dollar amount — up to the IRS-set annual limit, which for health care FSAs was $3,050 for plan years beginning in 2023 (IRS Revenue Procedure 2022-38) — during open enrollment before the plan year begins.
Availability: The full elected amount is available from the first day of the plan year, regardless of how much has been contributed via payroll deductions to date.
Spending window: The account holder submits claims for qualified medical expenses throughout the plan year. Claims may be submitted up to the run-out period deadline, which is a post-plan-year window (commonly 90 days) during which expenses incurred before year-end can still be reimbursed.
Forfeiture: Any balance remaining after the run-out period closes — or after any grace period or carryover extension expires — is forfeited. The employer retains these funds; they may be used to offset plan administrative costs.

The IRS does not require employers to offer any relief beyond the base rule. Employers may choose to offer one of two relief mechanisms: a grace period or a carryover provision. These are mutually exclusive — a single plan may not offer both (IRS Notice 2013-71).

Grace period: Allows up to 2.5 additional months after the plan year ends (e.g., through March 15 for a calendar-year plan) to incur new expenses against the prior year's balance.

Carryover: Allows up to $610 (for 2023 plan years, per IRS Revenue Procedure 2022-38) in unused FSA balances to roll forward into the following plan year. This limit is adjusted annually by the IRS.

Full detail on how these two options differ structurally is covered at FSA Grace Period vs. Carryover.

Common Scenarios

Scenario 1 — Full forfeiture (no employer extension). An employee elects $2,000 for a calendar-year FSA. By December 31, $1,400 has been spent on qualified expenses. The employer offers neither a grace period nor a carryover. The remaining $600 is forfeited as of January 1 of the following year.

Scenario 2 — Carryover plan. The same employee, under a plan offering the $610 carryover, forfeits only the $600 minus what carries forward — since $600 is under the $610 ceiling, the entire $600 rolls into the next plan year with zero forfeiture.

Scenario 3 — Grace period plan. The employee has $600 remaining on December 31. The employer offers a 2.5-month grace period. If the employee incurs $400 in qualifying expenses between January 1 and March 15, only $200 is ultimately forfeited.

Scenario 4 — Mid-year job change. An employee leaves employment on August 31 with $500 remaining in the FSA. COBRA continuation may allow continued FSA access for expenses through year-end, but this depends on plan terms and whether the employer offers FSA COBRA coverage. Without continuation, the remaining balance is forfeited upon termination. The FSA enrollment and mid-year changes page covers termination timing in greater detail.

Scenario 5 — Dependent care FSA. The use-it-or-lose-it rule also applies to dependent care FSAs, which carry a separate IRS contribution limit ($5,000 per household for 2023, per IRS Publication 503). Eligible expenses must be for qualifying dependents under age 13 or incapacitated dependents.

Decision Boundaries

The central planning decision is how much to elect at open enrollment. Several structural factors define the edges of that decision:

Predictability of expenses: A health care FSA is most efficient when annual medical, dental, and vision costs can be estimated with reasonable accuracy. The FSA Qualified Medical Expenses page outlines which expense categories are eligible.
Employer plan type: Whether the plan offers a grace period, carryover, or neither materially changes the risk exposure of over-election.
HSA compatibility: A general health care FSA makes an employee ineligible to contribute to an HSA. A Limited-Purpose FSA — restricted to dental and vision — is the only FSA type compatible with concurrent HSA enrollment. This boundary is detailed at Limited-Purpose FSA and FSA and HSA: Can You Have Both?.
Qualifying life events: Mid-year changes to FSA elections are permitted only under qualifying life events defined by IRS regulations, such as marriage, divorce, birth, or a change in employment status. Elections cannot generally be changed simply to avoid forfeiture.
Run-out vs. grace period deadlines: Missing the run-out period deadline means forfeiting expenses incurred before year-end but not yet submitted — a procedural loss, not a spending shortfall.

For account holders navigating the full landscape of tax-advantaged health accounts, the National Health Savings Authority home page provides an overview of how FSAs fit within the broader account ecosystem covered across this reference.

References

The law belongs to the people. Georgia v. Public.Resource.Org, 590 U.S. (2020)