{
  "$comment": "Illinois 2025: flat 4.95% on base income less $2850 exemption allowance per person (lost above AGI $250,000/$500,000 MFJ); no employee payroll programmes.",
  "country": "us",
  "jurisdiction": "us-il",
  "taxYear": "2025",
  "period": {
    "start": "2025-01-01",
    "end": "2025-12-31",
    "tz": "America/Chicago"
  },
  "status": "provisional",
  "engine": "us-payroll@1",
  "currency": "USD",
  "revision": 1,
  "params": {
    "incomeTax": {
      "kind": "brackets",
      "incomeBase": "stateWages",
      "brackets": {
        "single": [
          {
            "upTo": null,
            "rate": "0.0495"
          }
        ],
        "mfj": [
          {
            "upTo": null,
            "rate": "0.0495"
          }
        ],
        "mfs": [
          {
            "upTo": null,
            "rate": "0.0495"
          }
        ],
        "hoh": [
          {
            "upTo": null,
            "rate": "0.0495"
          }
        ]
      },
      "deductions": [
        {
          "type": "perPerson",
          "id": "exemption-allowance",
          "label": "Illinois exemption allowance (you, spouse, dependents)",
          "filer": {
            "single": "2850",
            "mfj": "5700",
            "mfs": "2850",
            "hoh": "2850"
          },
          "perDependent": "2850",
          "phaseout": {
            "single": {
              "threshold": "250000",
              "rate": "1",
              "floor": "0",
              "reductionRounding": {
                "unit": "1000000",
                "mode": "up"
              }
            },
            "mfj": {
              "threshold": "500000",
              "rate": "1",
              "floor": "0",
              "reductionRounding": {
                "unit": "1000000",
                "mode": "up"
              }
            },
            "mfs": {
              "threshold": "250000",
              "rate": "1",
              "floor": "0",
              "reductionRounding": {
                "unit": "1000000",
                "mode": "up"
              }
            },
            "hoh": {
              "threshold": "250000",
              "rate": "1",
              "floor": "0",
              "reductionRounding": {
                "unit": "1000000",
                "mode": "up"
              }
            }
          }
        }
      ],
      "credits": []
    },
    "conformity": {
      "k401": true,
      "k403b": true,
      "k457": true,
      "hsa": true,
      "healthFsa": true,
      "dependentCareFsa": true,
      "section125": true
    },
    "programmes": []
  },
  "rounding": {
    "unit": "0.01",
    "mode": "halfUp",
    "stage": "perLine"
  },
  "knownCliffs": [
    {
      "id": "il-exemption-cutoff",
      "field": "params.incomeTax.deductions",
      "description": "The whole exemption allowance ($2850 per person) is lost once federal AGI exceeds $250,000 ($500,000 MFJ), raising tax by 4.95% x the allowance at that point."
    }
  ],
  "notModelled": [
    "Additional $1,000 exemptions for age 65+ or blind",
    "Illinois EIC and Illinois child tax credit (depend on the federal EIC)",
    "Property tax, K-12 education expense and other credits",
    "Subtractions other than payroll pre-tax items"
  ],
  "sources": [
    {
      "field": "period",
      "url": "https://tax.illinois.gov/content/dam/soi/en/web/tax/forms/withholding/documents/2025/il-700-t.pdf",
      "title": "Booklet IL-700-T (2025) — calendar-year withholding/tax",
      "retrieved": "2026-10-07"
    },
    {
      "field": "rounding",
      "url": "https://tax.illinois.gov/content/dam/soi/en/web/tax/forms/incometax/documents/currentyear/individual/il-1040-instr.pdf",
      "title": "IL-1040 instructions; MoneyOtter rounds the annual line half-up to the cent",
      "retrieved": "2026-10-07"
    },
    {
      "field": "params.incomeTax.kind",
      "url": "https://tax.illinois.gov/content/dam/soi/en/web/tax/forms/withholding/documents/2025/il-700-t.pdf",
      "title": "State personal income tax on wages computed by rate schedule — Booklet IL-700-T (2025): tax rate 4.95%",
      "retrieved": "2026-10-07"
    },
    {
      "field": "params.incomeTax.brackets",
      "url": "https://tax.illinois.gov/content/dam/soi/en/web/tax/forms/withholding/documents/2025/il-700-t.pdf",
      "title": "Booklet IL-700-T (2025): tax rate 4.95%",
      "retrieved": "2026-10-07"
    },
    {
      "field": "params.incomeTax.brackets",
      "url": "https://tax.illinois.gov/content/dam/soi/en/web/tax/forms/incometax/documents/currentyear/individual/il-1040-instr.pdf",
      "title": "IL-1040 instructions: The Illinois income tax rate is 4.95 percent",
      "retrieved": "2026-10-07"
    },
    {
      "field": "params.incomeTax.deductions",
      "url": "https://tax.illinois.gov/content/dam/soi/en/web/tax/forms/incometax/documents/currentyear/individual/il-1040-instr.pdf",
      "title": "IL-1040 (2025) instructions Line 10: exemption allowance $2,850 per person; no allowance if federal AGI > $500,000 (MFJ) / $250,000 (other)",
      "retrieved": "2026-10-07"
    },
    {
      "field": "params.incomeTax.deductions",
      "url": "https://tax.illinois.gov/content/dam/soi/en/web/tax/forms/withholding/documents/2025/il-700-t.pdf",
      "title": "IL-700-T (2025): exemption allowance $2,850",
      "retrieved": "2026-10-07"
    },
    {
      "field": "params.incomeTax.incomeBase",
      "url": "https://tax.illinois.gov/content/dam/soi/en/web/tax/forms/incometax/documents/currentyear/individual/il-1040-instr.pdf",
      "title": "IL-1040 Line 1 federal AGI; wages-only taxpayer: base income = state wages",
      "retrieved": "2026-10-07"
    },
    {
      "field": "params.incomeTax.credits",
      "url": "https://tax.illinois.gov/content/dam/soi/en/web/tax/forms/incometax/documents/currentyear/individual/il-1040-instr.pdf",
      "title": "No standard personal credit; IL EIC/child tax credit (EIC-based), property tax and K-12 credits not modelled",
      "retrieved": "2026-10-07"
    },
    {
      "field": "params.conformity",
      "url": "https://tax.illinois.gov/content/dam/soi/en/web/tax/forms/incometax/documents/currentyear/individual/il-1040-instr.pdf",
      "title": "Illinois base income starts from federal AGI, so federally excluded pre-tax payroll items are excluded",
      "retrieved": "2026-10-07"
    },
    {
      "field": "params.programmes",
      "url": "https://tax.illinois.gov/content/dam/soi/en/web/tax/forms/withholding/documents/2025/il-700-t.pdf",
      "title": "No employee-paid Illinois payroll programme (UI employer-paid)",
      "retrieved": "2026-10-07"
    }
  ]
}