Paycheck / Take-Home Pay Estimator implementation

Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

Record owner

Guth Instruments

Lifecycle

verified-clean

Evidence ID

t7-056

Effect

Computation or source lookup only

Input and validation requirements

The specified instrument cannot produce complete nonzero paycheck results without year-stamped federal and state lookup tables. It also has a definite undefined-result trap when the pay-period denominator is zero, and it has a convention-sensitive deduction sign that can change the result by $400 in the probe.

Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

{
  "inputs": {
    "gross_pay": 100,
    "pay_frequency": "weekly",
    "pay_periods_per_year": 52,
    "filing_status": "single",
    "state": "TX",
    "pre_tax_deductions": 0,
    "deduction_type": "none",
    "tax_year": 2024
  },
  "expected_outputs": {
    "federal_withholding": 0,
    "social_security": 6.2,
    "medicare": 1.45,
    "fica_total": 7.65,
    "state_withholding": 0,
    "pre_tax_deductions": 0,
    "estimated_net_pay": 92.35
  },
  "reference_data": {
    "federal_standard_deduction_single_2024": {
      "value": 14600,
      "source_convention": "IRS 2024 federal tax parameters"
    },
    "federal_single_bracket_0_to_11600": {
      "rate": 0.1,
      "source_convention": "IRS 2024 federal tax brackets"
    },
    "texas_individual_income_tax": {
      "value": 0,
      "source_convention": "Texas Comptroller statutory convention: Texas has no individual state income tax"
    },
    "social_security_rate": {
      "value": 0.062,
      "source_convention": "IRS/SSA 2024 payroll-tax convention"
    },
    "medicare_rate": {
      "value": 0.0145,
      "source_convention": "IRS/SSA 2024 payroll-tax convention"
    }
  },
  "working": "Annualized gross = $100 × 52 = $5,200. Annualized federal taxable income = max($5,200 − $14,600, 0) = $0, so federal withholding = $0. Social Security = $100 × 6.2% = $6.20. Medicare = $100 × 1.45% = $1.45. FICA = $6.20 + $1.45 = $7.65. Texas withholding = $0. Net pay = $100 − $0 − $7.65 − $0 − $0 = $92.35. The $7.65 result is the widely memorized combined employee FICA rate on wages below the Social Security cap."
}

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche7/tranche7-results.json