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FSA Contribution Calculator

Pick a per-paycheck Flexible Spending Account amount that covers your expected costs, stays under the IRS cap, and shows the tax you save.

Expected eligible expenses this year

Paychecks per year

Marginal tax rate

Plan carryover allowed

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How it works

Election = min(expected eligible expenses, IRS cap $3,300 in 2025) · Per paycheck = election ÷ paychecks · Tax saved = election × marginal rate

A health FSA lets you set aside pre-tax salary for medical, dental and vision costs, so every dollar you route through it dodges income and FICA tax. The catch is the use-it-or-lose-it rule: unspent money is forfeited at year-end, except for a carryover (up to a plan-set limit) or a short grace period if your plan offers one. The right election is your realistic expected spending, capped at the IRS limit — aim to fund what you'll actually use, not the maximum.

Worked example

You expect $1,800 of copays and prescriptions and are paid bi-weekly. Electing $1,800 is $69.23 per paycheck. At a 30% combined marginal rate that saves about $540 in tax. If your plan carries over $660, only $1,140 is truly use-it-or-lose-it for the year.

Sources: IRS Rev. Proc. 2024-40 (2025 FSA limit)

Frequently asked questions

How is an FSA different from an HSA?

An FSA is owned by your employer, is use-it-or-lose-it, and does not require a high-deductible plan; an HSA is yours to keep forever, rolls over fully, and requires an HDHP. FSAs are fully funded on day one of the plan year, while HSAs fund as you contribute.

What happens to money I don't spend?

Unspent FSA funds are forfeited at the end of the plan year, unless your plan offers a carryover (a set dollar amount that rolls to next year) or a grace period of up to 2.5 extra months. Check which option your plan uses before you elect.

Can I change my election mid-year?

Usually only after a qualifying life event such as marriage, a birth or a change in employment. Otherwise your annual election is locked, which is why estimating expected expenses carefully up front matters.

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Educational estimate only, not insurance, tax or financial advice. Real premiums, contribution limits and costs depend on your carrier, plan, state and personal circumstances — get a quote and check current IRS limits.