Federal Health & Dependent Care FSA Calculator

How this calculator works

Flexible Spending Arrangements (FSAs) are the most widely used pretax health and dependent care vehicle in the federal tax code — and the most commonly mis-elected. Two distinct FSA archetypes coexist under IRC § 125 (the "Cafeteria Plan" provision): the Health FSA, which reimburses § 213(d) medical expenses up to a 2026 estimated $3,500 limit, and the Dependent Care FSA (DCFSA, IRC § 129), which reimburses child-care and dependent-care expenses up to a statutory $5,000 ($2,500 if married filing separately). Both are pretax payroll deferrals — the participant elects an annual amount at open enrollment, and the deferral is excluded from W-2 income tax wages AND from FICA wages, saving federal income tax + state income tax + 7.65% FICA on the deferred dollar. This calculator models both archetypes, the use-it-or-lose-it rule, the employer-elected carryover ($680 for 2026 estimated) and 2.5-month grace period safety valves (mutually exclusive), the forfeiture risk net of those buffers, and the structural tradeoffs versus IRC § 223 HSAs.

The two FSA archetypes

Health FSA (IRC § 125 + Treas. Reg. § 1.125-5): 2026 estimated annual contribution limit $3,500 (up from $3,425 in 2025 and $3,300 in 2024 — inflation-indexed under § 125(i) from a $2,500 base added by the Affordable Care Act). Qualified expenses are § 213(d) medical expenses: copays, deductibles, prescriptions, dental, vision, mental health, durable medical equipment, post-CARES Act over-the-counter drugs, and menstrual products. The Health FSA is pre-funded under the Treas. Reg. § 1.125-5(d) uniform coverage rule — the full annual election is available on Day 1 of the plan year, with the employer floating the money against future payroll deductions.

Dependent Care FSA (IRC § 129): $5,000 annual cap ($2,500 if married filing separately) — statutory under the Tax Reform Act of 1986 and NOT inflation-indexed in 40 years. Multiple legislative drafts have proposed indexing the cap, but only ARPA § 9632 (a one-year 2021 increase to $10,500) has been enacted, and the figure reverted to $5,000 for 2022. SECURE Act 2.0 maintained the $5,000 cap. Qualified expenses: care of children under age 13 OR disabled dependents while the taxpayer (and spouse if MFJ) works. DCFSA is NOT pre-funded — participants can only spend what has been contributed to date.

The use-it-or-lose-it rule

The fundamental risk of any FSA is the use-it-or-lose-it rule under Treas. Reg. § 1.125-5(c): any balance unspent on qualified expenses by plan-year end is forfeited to the employer (which can use the forfeited amounts to defray administrative costs or redistribute per the plan terms). The rule is the most significant downside of FSAs versus HSAs (where balances roll forward forever).

Two employer-elected safety valves modify the rule for Health FSAs only (DCFSAs have neither):

• Carryover (Notice 2013-71): Up to $660 for 2025; $680 estimated for 2026 (the cap is indexed at 20% of the annual limit, a methodology added by CAA 2021). Carryover applies forward indefinitely — the carryover amount adds to next year's election balance.
• Grace period (Notice 2005-42): Up to 2 months and 15 days after plan-year end (so for a calendar-year plan, through March 15 of the following year) during which qualified expenses incurred can be reimbursed from the prior year's balance.

The two are mutually exclusive — the employer must elect ONE, the OTHER, or NEITHER, but cannot offer both. Most large employers favor the carryover for administrative simplicity; smaller employers more often use the grace period.

Worked example 1 — $3,500 election with $3,000 expenses and carryover

A participant elects the full 2026 limit of $3,500 in Health FSA contributions through their employer's Section 125 cafeteria plan. The employer offers the carryover. Expected qualified medical expenses for the year: $3,000.

• Applicable limit: $3,500 (Health FSA 2026 est.)
• Actual contribution: $3,500
• Federal savings: $3,500 × 22% = $770
• State savings: $3,500 × 5% = $175
• FICA savings (always via § 125 payroll): $3,500 × 7.65% = $268 (actual $267.75)
• Total immediate tax savings: $770 + $175 + $268 = $1,213 (actual $1,212.75)
• Residual after expected expenses: $3,500 − $3,000 = $500
• Carryover absorbs: $500 (within the $680 cap)
• Expected forfeiture: $0
• Net benefit: $1,213 − $0 = $1,213
• Effective benefit rate: $1,213 / $3,500 = 34.7%

The carryover converts what would have been a $500 forfeiture into a $500 next-year balance. The participant captures the full 34.7% combined tax savings rate (federal 22% + state 5% + FICA 7.65%) with no forfeiture leakage.

Worked example 2 — $3,500 election with $2,000 expenses and no safety valve

Same $3,500 election, but the employer offers neither carryover nor grace period (a less common but still legitimate plan design). Expected qualified medical expenses: only $2,000.

• Actual contribution: $3,500
• Federal + state + FICA savings: $1,213 (same as Example 1)
• Residual after expected expenses: $3,500 − $2,000 = $1,500
• Carryover / grace absorb: $0 (neither elected)
• Expected forfeiture: $1,500
• Net benefit: $1,213 − $1,500 = −$287
• Effective benefit rate: −$287 / $3,500 = −8.2%

The participant has actually LOST money — the use-it-or-lose-it forfeiture of $1,500 exceeds the $1,213 of pretax savings. The lesson: size the election to expected expenses, not the statutory maximum, unless the employer offers a meaningful safety valve. A $2,000 election in this scenario would have produced ~$693 of net benefit with no forfeiture risk.

Worked example 3 — $3,500 election with $2,000 expenses and 2.5-month grace period

Same $3,500 election, only $2,000 of currently-known expected expenses — but the employer offers the 2.5-month grace period. The participant typically incurs additional expenses (prescription refills, dental cleanings, vision exams) in the January 1 – March 15 grace window.

• Actual contribution: $3,500
• Immediate tax savings: $1,213
• Forfeiture under the calculator's grace-period model: $0 (assumes expenses materialize in the grace window)
• Net benefit: $1,213
• Effective benefit rate: 34.7%

In practice, the participant may still forfeit if they don't spend during the grace period — the calculator's grace-period mode assumes the participant uses the additional 2.5 months to incur qualifying expenses. A defensible posture for participants who reliably have year-end and early-year medical activity.

Worked example 4 — $5,000 DCFSA, MFJ, two kids in daycare

A married-filing-jointly couple with two children in full-time daycare ($1,800/month) elects the full $5,000 DCFSA. Federal rate 22%, state rate 5%.

• Applicable limit: $5,000 (MFJ; $2,500 if MFS)
• Actual contribution: $5,000
• Expected expenses: $21,600 (well above the cap)
• Federal savings: $5,000 × 22% = $1,100
• State savings: $5,000 × 5% = $250
• FICA savings: $5,000 × 7.65% = $383 (actual $382.50)
• Total immediate tax savings: $1,100 + $250 + $383 = $1,733 (actual $1,732.50)
• Expected forfeiture: $0 (expenses vastly exceed contribution)
• Net benefit: $1,733
• Effective benefit rate: 34.7%

DCFSA forfeiture risk is generally low because most participants spend well above $5,000 annually on child care — the cap is the binding constraint, not expenses. The $5,000 cap has not changed since 1986 despite child-care costs rising several-fold; in real terms, the DCFSA covers a smaller and smaller share of actual child-care spend each year.

Worked example 5 — $5,500 election attempted on Health FSA

A participant attempts to elect $5,500 in Health FSA contributions, exceeding the 2026 $3,500 limit by $2,000.

• Applicable limit: $3,500
• Excess election: $2,000
• Actual deductible contribution: $3,500 (capped at the limit)

Unlike an HSA excess (which triggers the § 4973(g) 6% excise tax per year until corrected), an FSA excess is handled differently: the excess is included in W-2 wages. The pretax exclusion is denied for the excess and it shows up as taxable W-2 income — no separate excise tax applies, and no corrective distribution is required. The correction is automatic via payroll. The participant pays federal income tax + state + FICA on the $2,000 excess (no savings) but does not incur an additional penalty.

In practice, the payroll system will typically not allow an election above the statutory limit — the employer's benefits portal caps the deferral at the published cap. The W-2 inclusion mechanic exists for edge cases like a mid-year limit change or a multi-employer DCFSA where the household's combined deferral exceeds $5,000.

Health FSA vs HSA — structurally different vehicles

Health FSAs and HSAs are both pretax health-spending accounts but differ structurally:

• Rollover: HSA rolls forward forever; Health FSA is use-it-or-lose-it with at most $680 carryover (2026 est.) or 2.5-month grace period.
• Portability: HSA stays with the account holder forever (job changes, retirement); Health FSA is forfeited at employment separation (subject to COBRA continuation).
• Eligibility: HSA requires HDHP coverage under § 223(c)(2); Health FSA has no such requirement.
• Limit: 2026 estimated $4,400 self / $8,750 family HSA vs $3,500 Health FSA.
• Pre-funding: Health FSA full annual election available Day 1 under Treas. Reg. § 1.125-5(d); HSA only what's been contributed to date.
• Investment: HSA can be invested above a custodian minimum; Health FSA cannot.
• Mutual disqualification: A general-purpose Health FSA DISQUALIFIES HSA contributions under § 223(c)(1)(B). A limited-purpose FSA (dental/vision only) is HSA-compatible — most employers that offer both structure the FSA as limited-purpose to preserve HSA eligibility.

For HDHP-eligible households, the optimal stack is: HSA at max + limited-purpose FSA for predictable dental/vision spend + DCFSA at $5,000 for child care. The HSA captures long-horizon compounding; the limited-purpose FSA captures dental/vision pretax without disqualifying the HSA; the DCFSA captures child-care pretax with low forfeiture risk.

The pre-funding feature — a unique Health FSA advantage

The pre-funding feature under Treas. Reg. § 1.125-5(d) (the uniform coverage rule) requires that the full annual Health FSA election be available on Day 1 of the plan year. A participant who elects $3,500 in November (effective January 1) can spend the entire $3,500 in January even though they have contributed only $292 to date through payroll. If the participant separates from employment mid-year having spent more than they contributed, the employer absorbs the difference — the "orphan claim" scenario.

This makes the Health FSA materially more flexible than a savings account for known large early-year medical expenses: a planned surgery, LASIK ($2,000-$4,000), orthodontia ($3,000-$8,000), or a planned IVF cycle ($10,000-$20,000 with the FSA covering $3,500). The Health FSA functions like a 0% interest loan against future earnings for qualified medical spend. The DCFSA does NOT have the uniform coverage rule — participants can only spend what has been contributed to date.

Limited-purpose FSAs preserve HSA eligibility

A limited-purpose FSA reimburses ONLY dental and vision expenses (and, at employer election, post-deductible general medical expenses once the HDHP deductible is satisfied). Because it does not cover general medical expenses, it is NOT a "general-purpose health FSA" under § 223(c)(1)(B) — so it does NOT disqualify HSA contributions. The limited-purpose FSA captures the same tax savings (federal + state + FICA) as a general-purpose FSA on dental and vision spend, which is otherwise § 213(d) qualified for HSA reimbursement — but routing it through the FSA preserves HSA balance for other expenses and longer-horizon compounding.

Most employers that offer both an HSA and an FSA structure the FSA as a limited-purpose FSA to preserve HSA eligibility for HDHP-enrolled participants. Verify the FSA's scope on the Summary Plan Description — if it covers general medical expenses, it disqualifies the HSA.

Common errors

• Over-electing into forfeiture. Sizing the Health FSA election to the $3,500 maximum when expected expenses are only $2,000-$2,500 and the employer offers no safety valve. The forfeiture often exceeds the tax savings, producing a negative net benefit. Size the election to expected expenses minus the buffer.
• Confusing carryover with grace period. They are mutually exclusive — employer elects one or the other. Check the Summary Plan Description. Many participants assume their FSA has carryover when it actually has a grace period (or vice versa).
• Forgetting DCFSA has no carryover. DCFSA is pure use-it-or-lose-it under § 129. Size the DCFSA election conservatively — though for most participants with full-time child care, the $5,000 cap binds.
• General-purpose FSA destroying HSA eligibility. A spouse's general-purpose Health FSA covering the account holder under § 223(c)(1)(B) disqualifies the HSA — even if the account holder has individual HDHP coverage. The household must either drop the FSA or convert it to a limited-purpose FSA to preserve HSA eligibility.
• MFS reducing DCFSA to $2,500. Married-filing-separately filing status halves the DCFSA cap. Tax-planning the filing status can recover the lost cap; a CPA review of the joint-vs-separate filing tradeoff is generally worth running.
• Mid-year election changes without a qualifying event. FSA elections are irrevocable mid-year absent a qualifying life event under Treas. Reg. § 1.125-4 (marriage, divorce, birth, adoption, change in employment, etc.). Estimated expenses dropping mid-year is NOT a qualifying event — the participant is locked into the election.
• Not knowing CARES Act expanded the qualified expenses. Many participants don't realize that over-the-counter drugs (no prescription required, post-CARES Act § 3702 effective 1/1/2020) and menstrual products are now FSA-reimbursable. Stocking up on OTC drugs and menstrual products at year-end is a legitimate way to use down a Health FSA balance and avoid forfeiture.
• Missing the run-out window for claims submission. Most FSA administrators allow 60-90 days after plan-year end (or after grace period end) to SUBMIT claims for expenses already incurred — but the expense itself must have been incurred during the plan year (or grace period). Submitting late costs the participant the reimbursement.

This calculator is a planning tool, not advice. The 2026 Health FSA contribution limit and carryover cap are inflation-projected estimates pending the IRS's final release; verify against the published figures before relying on them for open-enrollment elections. State conformity to the federal Section 125 exclusion varies — confirm with a CPA for state-specific treatment. For an actual benefits election, run the figures against your employer's Summary Plan Description and the current IRS Publication 969, or, better, a CPA or benefits administrator who handles FSA planning as a regular practice. Tools, not advice.