Self-Employment Tax 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

t7-073

Effect

Computation or source lookup only

Input and validation requirements

The specification does not identify a tax year or provide the year-dated wage base and filing-status-dependent Medicare thresholds, so exact ordinary-case results are not determinate without external table data. It also does not define treatment of negative net earnings; literal application can produce a nonsensical negative tax. Extreme positive inputs can additionally lose precision.

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": {
    "tax_year": 2024,
    "net_SE_income_usd": 10000,
    "filing_status": "single",
    "employer_wages_usd": 0,
    "other_SE_income_usd": 0
  },
  "expected_outputs": {
    "adjusted_net_SE_earnings_usd": 9235,
    "social_security_tax_usd": 1145.14,
    "medicare_tax_usd": 267.82,
    "additional_medicare_tax_usd": 0,
    "estimated_SE_tax_usd": 1412.96,
    "quarterly_SE_tax_only_illustration_usd": 353.24
  },
  "reference_data": {
    "SE_adjustment_factor": {
      "value": 0.9235,
      "source_convention": "IRS Schedule SE standard statutory adjustment"
    },
    "social_security_rate": {
      "value": 0.124,
      "source_convention": "IRS/SSA 2024 standard self-employment Social Security rate"
    },
    "medicare_rate": {
      "value": 0.029,
      "source_convention": "IRS/SSA 2024 standard self-employment Medicare rate"
    },
    "additional_medicare_rate": {
      "value": 0.009,
      "source_convention": "IRS 2024 Additional Medicare Tax standard rate"
    },
    "social_security_wage_base_usd": {
      "value": 168600,
      "source_convention": "SSA 2024 contribution and benefit base"
    },
    "additional_medicare_threshold_single_usd": {
      "value": 200000,
      "source_convention": "IRS 2024 Additional Medicare Tax threshold"
    }
  },
  "working": "Adjusted earnings = 10,000.00 × 0.9235 = 9,235.00. Social Security tax = 9,235.00 × 0.124 = 1,145.14. Medicare tax = 9,235.00 × 0.029 = 267.815, rounded to 267.82. Additional Medicare base = max(0, 9,235.00 − 200,000.00) = 0, so additional tax = 0.00. Total = 1,145.14 + 267.82 + 0.00 = 1,412.96. Quarterly illustration = 1,412.96 ÷ 4 = 353.24."
}

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