Use It or Lose It: How to Spend Leftover FSA Money Before the Deadline

Health FSA money is use it or lose it unless your plan has a grace period or carryover. Learn the 2026 limits, why the date of care matters more than the date you pay, and how to use leftover funds on lab tests.

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September 25, 2026

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11 min read

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Health FSA money is use it or lose it. Money left in a health flexible spending account at the end of the plan year is forfeited unless your plan offers one of two exceptions: a grace period of up to 2½ months, or a carryover of unused funds, up to $680 for plan years beginning in 2026. A plan can offer one of these or neither, never both. An HSA is different: the balance rolls over from year to year with no deadline.

The detail most year-end advice skips is timing. For a health FSA, an expense generally counts in the plan year when you receive the care, not when you pay for it. If you buy a lab test on December 30 and have your blood drawn on January 6, that expense generally belongs to the new plan year. To use this year’s money, book the test and complete the draw before your plan year ends.

Quick summary

• FSAs are use it or lose it unless your plan has a grace period or a carryover.
• Grace period: up to 2½ extra months to incur new expenses with last year’s money.
• Carryover: up to $680 of unused 2026 funds can roll into the next plan year. The limit was $660 for 2025 plan years.
• Plans can offer one or neither, not both. Your plan documents say which.
• The date of care counts, not the date you pay. Complete the service within the plan year, or within your grace period.
• HSAs have no year-end deadline. Unused HSA money stays in the account.
• Lab tests are a qualified medical expense. Vitamins and supplements generally are not.

Is an FSA use it or lose it?

Yes. IRS Publication 969 describes health FSAs as generally “use-it-or-lose-it” plans: amounts left in the account at the end of the plan year can’t generally be carried over. Your employer can’t refund the unused balance to you.

There are two exceptions, and your employer chooses whether to offer either one:

• a grace period of up to 2½ months after the plan year ends, during which new expenses can be paid from the prior year’s balance; or
• a carryover of unused funds into the next plan year, up to an IRS limit that is adjusted each year for inflation.

A plan that adopts a carryover is not permitted to also offer a grace period for its health FSA, according to IRS Notice 2013-71 and Publication 969.

This guide covers health FSAs. Dependent care FSAs follow different rules and do not pay for medical care.

FSA grace period vs. carryover vs. run-out period

A grace period, a carryover, and a run-out period solve different problems. The first two let you spend leftover money on new care. The run-out period only gives you time to file claims for care you already received.

The run-out period is the one people most often confuse with a deadline extension. It does not let you spend on new care after the plan year ends. It only lets you submit paperwork for care that already happened. The IRS allows the reimbursement itself to be paid after the coverage period ends, as long as the expense was incurred during it.

To find which of these your plan has, check your summary plan description or benefits portal, or ask your FSA administrator. Plan years do not always follow the calendar year, so confirm your plan year’s end date too.

2026 FSA and HSA limits

The IRS adjusts FSA and HSA limits each year. These are the figures for 2026.

For plan years beginning in 2025, the health FSA limit was $3,300 and the maximum carryover was $660, according to Publication 969. Your employer can set a lower carryover than the IRS maximum.

When does an FSA expense count: the date of care, not the date you pay

For a health FSA, an expense generally counts in the plan year when the care is provided. Proposed IRS cafeteria plan regulations, which taxpayers may rely on until final regulations are issued, say medical expenses are incurred “when the employee (or the employee’s spouse or dependents) is provided with the medical care that gives rise to the medical expenses, and not when the employee is formally billed, charged for, or pays for the medical care” (Prop. Treas. Reg. §1.125-6(a)(2)(ii), 72 FR 43938). Publication 969 adds that a health FSA can’t make advance reimbursements of future or projected expenses.

For a lab test, the care is the specimen collection and the testing, not the checkout. This is what that means at year end:

• Buy and complete the draw before the plan year ends. The expense counts in this plan year, and your current FSA balance can pay for it.
• Buy in December, draw in January, with a grace period. The expense falls in the new plan year, but a grace period lets you pay for it from last year’s leftover money.
• Buy in December, draw in January, with a carryover. The expense falls in the new plan year. It can be paid from carried-over funds, up to your plan’s carryover amount.
• Buy in December, draw in January, with neither. The expense falls in the new plan year. Last year’s balance may not cover it, and that money may be forfeited.

Administrators apply these rules through their own claim processes, and some ask about the purchase date as well as the service date. The safest plan is to both pay for and complete the test within the plan year. If you cannot, ask your administrator how they treat the service date before you rely on a January appointment.

What can leftover FSA money pay for?

Health FSA money pays for qualified medical expenses, as defined in IRS Publication 502, subject to any limits your employer sets. Common year-end uses include:

• Lab tests. Laboratory fees that are part of medical care are a qualified medical expense.
• Over-the-counter medicines and menstrual care products, which Publication 969 lists as covered expenses whether or not they are prescribed.
• Copays, deductibles, and other out-of-pocket costs for medical, dental, and vision care.

Vitamins and supplements are generally not eligible. The IRS treats them as general health items unless a medical practitioner recommends them to treat a specific diagnosed condition. See are vitamins and supplements HSA or FSA eligible for how that exception works.

Using leftover FSA money on lab tests with Mito

You can use HSA or FSA funds on lab tests, panels, scans, and at-home test kits bought through Mito. These are generally eligible as qualified medical expenses.

How to pay with an FSA or HSA card

At checkout, choose “Pay with HSA/FSA.” Mito processes HSA and FSA payments through Flex, its payments partner. You enter your HSA or FSA card on the Flex checkout page.

• Itemized receipt. Flex emails an itemized receipt from notifications@withflex.com. Search for “Flex” or “withflex” if you can’t find it. That receipt is the document your administrator wants.
• Usually no LMN. Most Mito products are auto-substantiated through Flex, so they don’t usually require a Letter of Medical Necessity.
• One HSA or FSA card per purchase. Splitting one purchase across several HSA or FSA cards isn’t supported. If your balance doesn’t cover the full amount, pay the rest with a regular credit card on the Flex checkout page.
• Sales tax. Sales tax on eligible items is also covered by HSA or FSA funds.
• Supplements are not eligible. The “Pay with HSA/FSA” option does not appear when your cart contains a supplement. Buy lab tests in a separate order.

Leave time for the draw

Blood tests through Mito need a scheduled lab appointment. Your lab order form is generated when you schedule, and the lab needs it to draw your blood, so walking in without an appointment doesn’t work. You can book through your Mito dashboard or by messaging Mito Concierge, which can search available slots at nearby Quest, Labcorp, or BioReference locations.

Book early in December, since lab hours around the holidays vary by location.

At-home test kits are shipped to you and shipped back for testing, so they need more lead time than a blood draw. Order a kit early enough to collect your sample within the plan year, and ask your administrator which date they use for a kit if you are close to the deadline.

Results arriving in January do not change the date of care. Mito results typically arrive about 7 to 10 days after your lab visit.

If you are choosing a first test, start with the Mito marketplace or a cost guide such as vitamin D test cost or how much a blood test costs. For how self-pay lab testing works in general, see how to get lab tests without insurance.

HSA money does not expire

An HSA has no year-end deadline. Amounts that remain at the end of the year are generally carried over to the next year, and you don’t have to make withdrawals each year, according to Publication 969.

Two HSA rules still matter:

• Expenses must be incurred after you set up the HSA. Care you received before the account was established is not a qualified medical expense.
• Non-medical spending is taxed. A withdrawal not used for qualified medical expenses is taxable income and may face an additional 20% tax.

Keep your itemized receipts. You can pay for a qualified expense out of pocket now and reimburse yourself from the HSA later, as long as you can document the expense.

Year-end FSA checklist

1. Check your balance and your plan year’s end date.
2. Find out whether your plan has a grace period, a carryover, or neither, and the run-out date for submitting claims.
3. List care you can complete before the deadline, such as a lab test you have been putting off.
4. Book the appointment, and complete the draw or ship the kit before the plan year ends.
5. Save each itemized receipt and submit claims before the run-out deadline.

Frequently asked questions

• What happens to unused FSA money? Unused health FSA money is forfeited to the plan at the end of the plan year, unless your plan has a grace period or a carryover. Your employer can’t pay the balance out to you.
• Is the FSA deadline always December 31? No. The deadline is the end of your plan year, which your employer sets. Many plans follow the calendar year, but not all do.
• Can I have both a grace period and a carryover? No. A health FSA with a carryover is not permitted to also offer a grace period. It can offer one or neither.
• Does carried-over money reduce what I can contribute next year? No. Publication 969 says the carryover doesn’t affect the maximum amount of salary reduction contributions you can make.
• Can I buy a lab test now and use it next year? You can, but the expense generally counts in the plan year when your blood is drawn, not when you pay. To use this year’s balance, complete the draw within this plan year or your grace period.
• Does a limited-purpose FSA cover lab tests? It depends on your plan. Limited-purpose FSAs, often paired with an HSA, pay for dental, vision, and preventive care. Ask your administrator whether a specific lab test qualifies.

References

1. Internal Revenue Service. Publication 969 (2025), Health Savings Accounts and Other Tax-Favored Health Plans. https://www.irs.gov/publications/p969. Accessed September 2026.
2. Internal Revenue Service. Publication 502 (2025), Medical and Dental Expenses. https://www.irs.gov/publications/p502. Accessed September 2026.
3. Internal Revenue Service. Revenue Procedure 2025-32, section 4.15, Cafeteria Plans. Internal Revenue Bulletin 2025-45. https://www.irs.gov/irb/2025-45_IRB. Accessed September 2026.
4. Internal Revenue Service. Revenue Procedure 2025-19, 2026 inflation-adjusted amounts for Health Savings Accounts. Internal Revenue Bulletin 2025-21. https://www.irs.gov/irb/2025-21_IRB. Accessed September 2026.
5. Internal Revenue Service. Notice 2013-71, Modification of “Use-or-Lose” Rule for Health Flexible Spending Arrangements. https://www.irs.gov/pub/irs-drop/n-13-71.pdf. Accessed September 2026.
6. Department of the Treasury, Internal Revenue Service. Employee Benefits: Cafeteria Plans, proposed rule. Federal Register 72(150):43938-43968, August 6, 2007. Proposed §1.125-6(a)(2). https://www.govinfo.gov/content/pkg/FR-2007-08-06/html/E7-14827.htm. Accessed September 2026.