{
  "slug": "hsa-vs-fsa-savings-cost",
  "title": "HSA vs FSA Savings Calculator",
  "heading": "HSA vs FSA Calculator",
  "category": "financial",
  "url": "https://www.revenuelab.fyi/toolbox/hsa-vs-fsa-savings-cost",
  "summary": "Compare the tax savings, rollover rules, and long-term value of an HSA against an FSA.",
  "description": "An HSA offers triple tax advantages and unlimited rollover but requires a high-deductible health plan, while an FSA lowers your taxable income too but is typically use-it-or-lose-it each year. This tool compares your effective tax savings from contributions, the value of any employer match, and the cost of unused-funds forfeiture to show which account nets you more over your planning horizon.",
  "formula": "Net Value = Contribution × Marginal Tax Rate + Employer Match − Forfeited Funds (FSA only) − Investment Growth Lost.",
  "dateModified": "2026-09-06",
  "run_url": "https://www.revenuelab.fyi/api/public/calc?tool=hsa-vs-fsa-savings-cost",
  "inputs": [
    {
      "id": "annualContribution",
      "label": "Annual contribution",
      "kind": "number",
      "hint": null,
      "default": 3000,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "marginalTaxRate",
      "label": "Marginal tax rate",
      "kind": "number",
      "hint": null,
      "default": 24,
      "unit": "%",
      "min": 0,
      "max": 50
    },
    {
      "id": "employerMatch",
      "label": "Employer HSA contribution",
      "kind": "number",
      "hint": null,
      "default": 500,
      "unit": "$",
      "min": 0,
      "max": null
    },
    {
      "id": "fsaForfeitPercent",
      "label": "Expected FSA forfeiture",
      "kind": "number",
      "hint": null,
      "default": 10,
      "unit": "%",
      "min": 0,
      "max": 100
    },
    {
      "id": "years",
      "label": "Years to project (HSA growth)",
      "kind": "number",
      "hint": null,
      "default": 10,
      "unit": null,
      "min": 1,
      "max": 30
    },
    {
      "id": "hsaGrowthRate",
      "label": "HSA investment growth rate",
      "kind": "number",
      "hint": null,
      "default": 6,
      "unit": "%",
      "min": 0,
      "max": 15
    }
  ],
  "outputs": [
    {
      "id": "winner",
      "label": "Higher net value account",
      "format": "raw",
      "hint": null,
      "primary": true
    },
    {
      "id": "hsaTotal",
      "label": "HSA total value (with growth)",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "fsaTotal",
      "label": "FSA total net savings",
      "format": "currency",
      "hint": null,
      "primary": false
    },
    {
      "id": "diff",
      "label": "Difference over horizon",
      "format": "currency",
      "hint": null,
      "primary": false
    }
  ],
  "worked_example": {
    "inputs": [
      "Annual contribution: 3000 $",
      "Marginal tax rate: 24 %",
      "Employer HSA contribution: 500 $",
      "Expected FSA forfeiture: 10 %",
      "Years to project (HSA growth): 10",
      "HSA investment growth rate: 6 %"
    ],
    "outputs": [
      "Higher net value account: HSA",
      "HSA total value (with growth): $16,081",
      "FSA total net savings: $4,200",
      "Difference over horizon: $11,881"
    ]
  },
  "how_to": {
    "title": "How to use this",
    "steps": [
      "Enter annual contribution ($).",
      "Enter marginal tax rate (%).",
      "Enter employer hsa contribution ($).",
      "Enter expected fsa forfeiture (%).",
      "Enter years to project (hsa growth).",
      "Enter hsa investment growth rate (%).",
      "Read your higher net value account on the right — it updates as you type.",
      "Hit Share to keep the scenario or send it to someone."
    ]
  },
  "scenarios": [
    {
      "name": "Conservative",
      "description": "Lower-end numbers — what if things land soft?",
      "values": {
        "annualContribution": 1800,
        "marginalTaxRate": 14,
        "employerMatch": 300,
        "fsaForfeitPercent": 5,
        "years": 6,
        "hsaGrowthRate": 3.5999999999999996
      }
    },
    {
      "name": "Typical",
      "description": "Defaults — the most common real-world setup.",
      "values": {
        "annualContribution": 3000,
        "marginalTaxRate": 24,
        "employerMatch": 500,
        "fsaForfeitPercent": 10,
        "years": 10,
        "hsaGrowthRate": 6
      }
    },
    {
      "name": "Ambitious",
      "description": "Higher-end numbers — what if things really pop?",
      "values": {
        "annualContribution": 4800,
        "marginalTaxRate": 38,
        "employerMatch": 800,
        "fsaForfeitPercent": 15,
        "years": 16,
        "hsaGrowthRate": 9.600000000000001
      }
    }
  ],
  "limitations": [
    "Results are estimates before tax, fees, and inflation unless an input explicitly covers them.",
    "Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.",
    "This is educational maths, not financial advice. Check anything contractual with the lender or your accountant."
  ],
  "faq": [
    {
      "q": "Can I have both an HSA and FSA?",
      "a": "Generally no — you can't contribute to a standard HSA and a general-purpose FSA in the same year, though a limited-purpose FSA (dental/vision only) can be paired with an HSA."
    },
    {
      "q": "What happens to unused HSA funds?",
      "a": "They roll over indefinitely and stay yours even after you change jobs or retire, unlike most FSAs which reset annually with only a small carryover or grace period allowed."
    },
    {
      "q": "Is an HSA worth it if I rarely have medical expenses?",
      "a": "Yes — it functions as a stealth retirement account since unused funds can be invested and withdrawn penalty-free for any reason after age 65, taxed like a traditional IRA."
    }
  ],
  "related": [
    "https://www.revenuelab.fyi/toolbox/high-vs-low-deductible-plan-cost",
    "https://www.revenuelab.fyi/toolbox/roth-vs-traditional"
  ],
  "license": "CC-BY-4.0",
  "citation": "RevenueLab — HSA vs FSA Savings Calculator (https://www.revenuelab.fyi/toolbox/hsa-vs-fsa-savings-cost)"
}