What Happens If I Don’t Submit Receipts for FSA?

If you don’t submit receipts for an FSA charge that your plan administrator flags, a fixed correction process kicks in: your FSA debit card is deactivated, your employer demands repayment, unpaid amounts can be withheld from your paycheck or offset against future claims, and anything still outstanding is added to your taxable wages on your W-2. The sequence is set by IRS rules, and skipping steps isn’t an option your employer has, because a plan that lets unsubstantiated charges slide risks losing its tax-favored status for every employee enrolled in it.

The Five-Step Correction Sequence

IRS guidance under Proposed Treasury Regulation Section 1.125-6 tells employers exactly how to handle an FSA debit card charge that can’t be verified. Plan administrators treat it as the standard playbook.¹ The steps run in order, and each one only triggers if the previous one hasn’t resolved the charge:

The FSA debit card is shut off until the issue is cleared.
Your employer formally demands that you repay the unsubstantiated amount.
If you don’t repay, the employer withholds the amount from your pay to the extent the law allows.
Any leftover balance is offset against future verified FSA reimbursements.
If none of that fully recovers the money, the employer treats what remains as a business debt owed by an employee.

Most people resolve things at step one or two by submitting the missing receipt. The later steps exist for cases where someone ignores repeated notices or genuinely can’t document the expense.

Your FSA Debit Card Gets Suspended

The first thing you’ll notice is that your card stops working. When a charge can’t be verified automatically, your plan administrator sends a request for documentation. The response window is typically 30 to 60 days depending on your employer’s plan. Miss it, and the card is deactivated.¹

Deactivation is not the same as losing your balance. The money is still in your account, and you can still be reimbursed for new eligible expenses. You just have to pay out of pocket and file manual claims with full documentation until the flagged charge is resolved. The card turns back on once you either send in the missing receipt or repay the amount.

Repayment and Payroll Withholding

If a receipt never turns up, your employer is required to formally ask you to repay an amount equal to the unsubstantiated charge back into the cafeteria plan.² The IRS guidance doesn’t dictate a specific payment method, so employers use whatever their normal process is, typically a check or electronic payment.

Ignore the demand and the employer can withhold the amount from your paycheck “to the full extent allowed by applicable law.”¹ That qualifier does real work. Federal law prohibits any deduction that would push your earnings below the applicable minimum wage or eat into required overtime pay.³ Many states set stricter limits, so how much your employer can actually recover through withholding depends on where you work.

Offsetting the Charge With a Different Receipt

Before this turns into a tax problem, look for a different receipt. If you paid for any qualifying medical expense out of pocket during the same coverage period and haven’t submitted it for reimbursement yet, you can use that expense to cancel out the unverified charge.¹

The math is simple. If you have a $200 unsubstantiated charge and you submit a verified $250 claim, the administrator applies the $200 offset and reimburses you the remaining $50. The substitute expense can’t have been reimbursed already by your FSA, insurance, or any other source. Any unused medical receipts from the plan year sitting in a drawer become useful here.

The Tax Consequence: Reclassification as Wages

When no receipt comes in, no repayment happens, and no offset is available, the unsubstantiated amount is added to your taxable wages on your W-2. This is the outcome that matters most, because it’s the one that lingers past the plan year.

Once reclassified, the amount is subject to federal income tax at your marginal rate plus Social Security tax at 6.2% and Medicare tax at 1.45%, for a combined FICA hit of 7.65%.⁴ On a $500 unsubstantiated charge, that’s about $38 in payroll taxes on its own. For someone in the 22% federal bracket, the total extra tax on that $500 lands around $148. You already spent the money; now you owe tax on it as if it had been ordinary pay.

What Counts as a Valid Receipt

A credit card slip won’t cut it. Valid substantiation has to show four things: the provider or merchant name, the date of service, a description of what the medical service or product was, and the amount you were responsible for paying. A “balance forward” statement, a cancelled check, or a payment confirmation that doesn’t describe the service will be rejected, because none of them prove what the money was actually spent on.

An Explanation of Benefits from your insurance company is the cleanest option because it contains all four elements. At a provider’s office, ask for an itemized receipt, not just a payment slip. For over-the-counter items, the receipt must show the specific product name.

Dual-purpose items, meaning things that could be either medical or general use, need a Letter of Medical Necessity from your doctor stating the item is medically required.⁵ Air purifiers, ergonomic chairs, and certain supplements fall into this category. Get the letter before the purchase if you can.

Deadlines That Limit Your Options

Timing shapes what you can still do about an unsubstantiated charge. FSAs run on a “use-it-or-lose-it” basis, so leftover funds at the end of the plan year are generally forfeited.⁶ Your plan may offer one of two softeners, but not both:⁷

A grace period of up to 2½ months after the plan year ends to incur new eligible expenses using leftover funds. For a calendar-year plan, that pushes the spending deadline to March 15.
A carryover of up to $680 of unused funds into the next plan year for 2026. Anything above that cap is forfeited, and the carryover doesn’t count against the next year’s $3,400 contribution limit.

The deadline that actually controls whether you can fix an unsubstantiated charge is the run-out period. This is the window after the plan year ends, typically 90 days, during which you can still submit receipts for expenses incurred during the plan year. Miss it, and the substitute-receipt route closes. If your run-out period is nearing its end and you have a flagged charge, that’s the deadline to focus on.

If You Leave Your Job With Unsubstantiated Claims

Termination complicates things. Federal guidance does not let employers withhold FSA overpayments from a departing employee’s final paycheck or bill you for the difference after you’re gone. The employer generally absorbs the loss on the plan side.

The tax side is a different story. An unresolved unsubstantiated amount can still be reclassified as taxable wages on your final W-2 for the year. You also lose access to the FSA debit card immediately on separation, though you can still submit manual claims for expenses incurred before your termination date during any remaining run-out period. FSA continuation coverage (sometimes called FSA COBRA) is available in some cases if you want to keep contributing and spending from the account.

Appealing a Denial

If your plan administrator rejects a receipt or labels a charge unsubstantiated and you disagree, ERISA gives you appeal rights. You have at least 180 days from the denial to file an appeal, and the reviewer has to decide independently rather than defer to the original decision.⁸ For standard post-service claims, the plan has 30 days to issue a decision.

Most substantiation disputes come down to paperwork rather than eligibility. Ask for a specific explanation of what was missing from the rejected documentation and resubmit with the right details. When the amount is large enough to matter, appealing is worth it, because the alternative is repayment now or added tax later.

1
Department of the Treasury Internal Revenue Service. Proposed Income Tax Regulations Under Section 125 (REG-142695-05)
2
Internal Revenue Service. IRS Chief Counsel Memorandum 201413006
3
U.S. Department of Labor. Fact Sheet 16 Deductions From Wages for Uniforms and Other Facilities Under the Fair Labor Standards Act (FLSA)
4
Internal Revenue Service. Topic No. 751, Social Security and Medicare Withholding Rates
5
FSAFEDS. FSAFEDS Letter of Medical Necessity
6
Internal Revenue Service. Publication 969 (2025), Health Savings Accounts and Other Tax-Favored Health Plans
7
Internal Revenue Service. Notice 2013-71, Modification of Use-or-Lose Rule for Health Flexible Spending Arrangements
8
U.S. Department of Labor. Benefit Claims Procedure Regulation FAQs