A health Flexible Spending Account (FSA) lets you set aside pre-tax payroll dollars for eligible medical expenses. The tradeoff is timing: many plans still run on use-it-or-lose-it, with either a short grace period or a limited carryover—rarely both. Misread the plan document and you can forfeit cash you already earned.
This guide covers the rules that trip people up at year-end. For product choice (HSA vs FSA vs limited-purpose), start with HSA and FSA basics. How the FSA sits inside open-enrollment menus: Cafeteria / Section 125 plans. Dependent care accounts follow different IRS limits—see Dependent care FSA and the DCFSA vs tax credit tradeoff.
Use-it-or-lose-it in practice
| Rule | What it means | What you should do |
|---|---|---|
| Plan year election | You choose a contribution amount during open enrollment; mid-year changes usually need a qualifying life event | Elect from a realistic expense forecast, not a guess |
| Uniform coverage (health FSA) | You can often spend the full election early in the year | Still repay via payroll; leaving the job can trigger collections |
| Use-it-or-lose-it | Unspent amounts may be forfeited after the deadline | Track balance monthly from November on |
| Grace period (optional plan design) | Extra ~2.5 months after year-end to incur claims (common design; confirm yours) | Calendar the last day to incur expenses, not just submit |
| Carryover (optional plan design) | Limited dollar amount may roll to next year (IRS cap can change by year) | Confirm whether your plan uses carryover or grace period |
| Run-out period | Time after year-end to submit claims for prior-year expenses | Save EOBs and receipts; portals close |
Employers and administrators you will see on cards and portals include HealthEquity, WEX, Fidelity benefits sites, Optum Bank (in some setups), and in-house HR tools. The SPD / plan summary beats whatever a coworker remembers from last year.
Grace period vs carryover (pick what your plan has)
IRS rules generally prevent a health FSA from offering both a full grace period and a carryover in the same plan design. Your HR summary should state which feature applies. Calendar and spend-down detail: FSA grace periods and year-to-year FSA carryover.
- Grace period focus: Incur eligible expenses quickly in January–mid-March (typical window) for leftover prior-year dollars, then submit before run-out ends.
- Carryover focus: A capped amount rolls; anything above the cap is still at risk. Plan next year’s election with the carryover in mind.
Dependent care FSAs have their own timing and generally do not use the same carryover rules as health FSAs—read that plan separately.
Worked example
Sam elected $2,000 for the 2026 health FSA at a company using carryover (illustrative cap $640). By December 1 Sam has $820 left.
| Move | Result |
|---|---|
| Buy eligible glasses + dental cleaning + OTC basics totaling $820 before Dec 31 | $0 forfeit (if expenses qualify and are incurred in time) |
| Spend nothing; rely on carryover | ~$640 rolls; ~$180 forfeited (illustrative) |
| Assume a grace period that the plan does not offer | Risk forfeiting most of the $820 |
Sam checks the portal label—“carryover eligible”—and schedules an eye exam in December rather than hoping for a grace period myth.
For the open-enrollment choice between a healthcare FSA and an HSA (when you are HDHP-eligible), see Healthcare FSA vs HSA.
Eligible expenses and documentation
Category map (what usually qualifies vs common denials): FSA-eligible expenses.
Common fits: deductibles, copays, coinsurance, many prescriptions, and eligible dental/vision costs aligned with IRS Publication 502-style lists. Pair big medical timing with Health insurance deductibles. Keep itemized receipts; card swipes alone may fail audit.
FSA elections also interact with tax filing workflows when you reconcile benefits—but the FSA itself is usually reported via W-2 box nuances and plan administrators, not a DIY deduction you invent in April. For filing basics, see Filing taxes for beginners.
Mid-year job change
Leaving an employer often ends contributions and can cut off access for expenses incurred after your last day (COBRA FSA continuation is limited and plan-specific). Spend intentionally before you exit when the balance is yours to use, and ask HR for the exact termination and run-out rules in writing.
Checklist
- Download this year’s plan summary; circle grace period or carryover (and the dollar cap).
- Set a Nov 1 calendar reminder to check the FSA balance.
- List planned eligible expenses before you elect at open enrollment.
- Save receipts and EOBs in one folder per plan year.
- Confirm OTC eligibility and any Rx requirements before you stockpile.
- If changing jobs, ask HR about last-day incur rules and run-out dates.
Educational only. Not tax, legal, or benefits advice. IRS limits, carryover caps, and plan designs change by year and employer; verify with your plan administrator and current IRS FSA guidance.