FSA Deadlines: Grace Period, Carryover, and Run-Out Are Three Different Things That Get Confused Constantly
"Use it or lose it" is the phrase everyone associates with flexible spending accounts, and it's technically accurate as a default rule — but most plans soften it with one of two relief mechanisms, and confusing which one your plan uses with the plain claims-filing deadline is one of the most common FSA mistakes.
Three deadlines, three different jobs
A grace period extends the window during which new eligible expenses can be incurred against last year's remaining balance — commonly 2.5 months past plan year end. A carryover instead rolls a capped dollar amount of unused funds directly into the next plan year, with no grace period attached and no requirement to incur anything new. A run-out period is different from both: it's simply the deadline to submit paperwork for an expense that was already incurred during the plan year (or during a grace period, if one applies), regardless of whether a carryover or grace period exists at all.
A plan can offer one relief mechanism, never both
IRS guidance requires an employer to pick either a grace period or a carryover for a given plan year — not both simultaneously. Some plans offer neither, relying purely on the standard run-out window for filing claims on expenses already incurred before the strict use-it-or-lose-it rule applies. Knowing which one (if any) your specific plan has adopted changes both how you should spend down a balance late in the year and how much of it might survive into the next one.
The run-out deadline applies no matter what
Whether or not a grace period or carryover exists, the run-out period is still the operative deadline to actually file paperwork for anything already spent. It's common — and financially costly — to assume a grace period means there's no rush to file claims, when in fact the run-out deadline for filing is a completely separate clock that keeps ticking regardless of which spending-extension rule applies.
Confirm your plan's specific rules first
Nothing about which relief mechanism a plan uses is standardized — some employers offer a grace period, some a carryover at whatever dollar limit the IRS currently allows, and some neither. Check your plan documents or benefits administrator before assuming any particular rule applies to your account.
Map your specific plan's deadlines
The FSA Grace Period & Run-Out Deadline calculator takes your plan year end, which relief mechanism (if any) your plan offers, and your plan's run-out period length, and returns the deadlines that actually apply — separating the spending-extension question from the claims-filing question so the two don't get conflated.