{
  "tool_id": "art-338-compute-federal-withholding",
  "kernel_id": "art-338-compute-federal-withholding",
  "display_name": "Federal Withholding Calculator (Percentage Method)",
  "tool_version": "1.0.0",
  "mandate_type": "compliance_mandate",
  "purpose": "Federal income tax withholding via the IRS Publication 15-T (2025) percentage method, Worksheet 1A, for a 2020-or-later Form W-4. Supports single/MFS, married filing jointly, and head of household, plus Step 3 dependents credit, Step 4(a) other income, Step 4(b) deductions, and Step 4(c) extra withholding. STANDARD Withholding Rate Schedules only; the Form W-4 Step 2 multiple-jobs checkbox table is out of scope for v1. Federal only, not tax advice, state withholding out of scope. Feeds art-339-compute-gross-to-net as its federal_withholding_per_period input. Not compute_gross_to_net itself, which adds FICA and produces net pay.",
  "control_description": "Federal income tax withholding via the IRS Publication 15-T (2025) percentage method, Worksheet 1A, for a 2020-or-later Form W-4. Supports single/MFS, married filing jointly, and head of household, plus Step 3 dependents credit, Step 4(a) other income, Step 4(b) deductions, and Step 4(c) extra withholding. STANDARD Withholding Rate Schedules only; the Form W-4 Step 2 multiple-jobs checkbox table is out of scope for v1. Federal only, not tax advice, state withholding out of scope. Feeds art-339-compute-gross-to-net as its federal_withholding_per_period input. Not compute_gross_to_net itself, which adds FICA and produces net pay.",
  "declared_inputs": [],
  "declared_outputs": [
    "art-339-compute-gross-to-net"
  ],
  "kernel_digest": "sha256:510689cdacc57d0934a872451735f41f2e58e4b71158ca7acf61f3738a74936b",
  "trust_label": "independently verified: zkVM execution proof (risc0/groth16-bn254)",
  "data_vintage": "2026-07-17",
  "last_validated": "2026-07-17",
  "conformance_fixtures_vendored": true,
  "compute_proof_ready": "ready",
  "wave": 60,
  "source_url": "https://ainumbers.co/chaingraph/art-338-compute-federal-withholding.html",
  "generated_at": "2026-08-15T11:12:17.704Z"
}