No, you cannot enroll in an FSA anytime. Enrollment is limited to three windows: your employer’s annual open enrollment period, a short window when you first start a job, and a special window opened by a qualifying life event such as marriage, divorce, or the birth of a child. Outside those windows, federal rules treat your election as locked in for the plan year.1Internal Revenue Service. Notice 2022-41 – Additional Permitted Election Changes for Health Coverage For 2026, the health FSA contribution cap is $3,400 and the dependent care FSA cap rises to $7,500 per household.
Open Enrollment Is the Main Window
Most employers run open enrollment for a few weeks in the fall, typically between October and December. During that window you decide whether to participate and how much to contribute for the upcoming plan year. Once the plan year begins, your election is fixed. Cafeteria plan elections are treated as irrevocable for the coverage period unless a specific exception applies.1Internal Revenue Service. Notice 2022-41 – Additional Permitted Election Changes for Health Coverage
That irrevocability has real consequences. Elect $3,400 for a health FSA and find your medical bills lower than expected, and you cannot dial the amount back. Skip enrollment entirely and you are out for the whole year. At the start of the plan year you designate the annual amount, and your employer deducts equal pre-tax portions from each paycheck.2Internal Revenue Service. Publication 969 (2025), Health Savings Accounts and Other Tax-Favored Health Plans
Health FSA elections do not automatically roll over in most plans. If you were enrolled last year, you generally have to elect again for the new year during open enrollment.
Enrollment When You Start a New Job
Starting a new job opens its own window separate from the annual cycle. Most employers give new hires 30 to 60 days from the start date to elect FSA benefits. Some make you eligible immediately; others begin coverage on the first day of the month after your hire date.
If you enroll partway through the plan year, your contribution is typically prorated across the paychecks remaining in the year, so you are not expected to hit the full annual maximum on a shortened schedule. One quirk favors new health FSA participants: your entire annual election is available from day one of coverage even though payroll deductions accumulate over the rest of the year. This is the uniform coverage rule.3Internal Revenue Service. Notice 2013-71 – Modification of Use-or-Lose Rule for Health FSAs You could submit a claim for the full elected amount on your first eligible day.
Dependent care FSAs work differently. Your balance builds only as payroll deductions accumulate, and you cannot spend money that has not yet been contributed. That distinction matters when you decide how aggressively to fund each account after a new hire date.
Miss your new-hire window and the consequence is the same as missing open enrollment: you wait until the next annual period. Plan rules follow federal tax law, and HR cannot open the door as a favor.
Qualifying Life Events: The Only Mid-Year Door
The one reliable way to enroll or change an FSA outside open enrollment is a qualifying life event. Treasury regulations allow cafeteria plans to permit mid-year changes when your personal circumstances shift in specific ways.4eCFR. 26 CFR 1.125-4 – Permitted Election Changes Note the word “permit.” Your employer’s plan does not have to recognize every event the regulations allow, so check your plan documents to see what actually counts.
Events that commonly open a change window include:
- Marriage or divorce. Getting married might justify increasing a health FSA to cover a spouse’s co-pays. A divorce might justify reducing dependent care contributions.
- Birth or adoption of a child. Adding a dependent typically supports increases to both health and dependent care elections.
- A change in employment status, such as moving between part-time and full-time, or a spouse gaining or losing employer coverage.
- A significant change in dependent care costs, such as a daycare provider raising or lowering its rates. This can support a dependent care FSA adjustment even without a traditional life event.
There is an important limit: any change has to be consistent with the event that triggered it. A new baby does not let you slash your health FSA because you feel you over-contributed. The adjustment must logically follow from the life change, and employers typically ask for documentation like a birth certificate or marriage license.
Most plans give you 30 days from the date of the event to notify your benefits administrator. Some extend that to 60 days for birth or adoption. The exact figure is set by your employer’s plan document, not by a single federal rule, so the deadline varies. The clock starts on the date of the event itself, not the date you get around to calling HR.4eCFR. 26 CFR 1.125-4 – Permitted Election Changes Miss the window and you are stuck with your current election, or with no election at all, until the next open enrollment.
2026 Contribution Limits
Knowing the caps matters when you finally get an enrollment window, because you set the annual amount at the moment you enroll.
Health FSA
For plan years beginning in 2026, you can contribute up to $3,400 through salary reductions to a health FSA, up from $3,300 in 2025.5FSAFEDS. New 2026 Maximum Limit Updates Contributions come out of your paycheck before federal income tax, Social Security, and Medicare are calculated.6Internal Revenue Service. Eligible Employees Can Use Tax-Free Dollars for Medical Expenses
Some employers add matching or seed contributions. Those employer dollars generally do not count against your $3,400 limit unless you have the option to take the money as cash instead. If cash is an option, the IRS treats the contribution as your own salary reduction, and it counts.
Dependent Care FSA
The dependent care FSA limit rises to $7,500 per household for tax years beginning after December 31, 2025, up from the longstanding $5,000. Married filing separately is capped at $3,750.7Office of the Law Revision Counsel. 26 USC 129 – Dependent Care Assistance Programs A qualifying dependent can be a child under 13, a disabled spouse, or an elderly parent who needs care so you can work. This cap is not indexed for inflation and will stay at $7,500 until Congress changes it again.
Deadlines to Keep in Front of You
The enrollment question is really a deadline question. The dates that decide whether you get an FSA at all:
- Open enrollment: dates set by your employer, usually a few weeks in the fall. No election during this window means no FSA for the coming year.
- New-hire enrollment: typically 30 to 60 days from your start date, depending on employer policy.
- Qualifying life event: typically 30 days from the event to notify your employer, sometimes 60 days for birth or adoption. Your plan document controls.
Benefits administrators cannot extend these deadlines as a courtesy. The tax-advantaged status of the account depends on following the rules as written in the plan document, and those rules track IRS requirements. If you have had a qualifying event, report it right away rather than sitting on it.