Payroll Deduction Code Audit 2026

Twelve rules run over your deduction-code map: Roth flagged pre-tax, garnishment flagged pre-tax, missing tax treatment, duplicate code conflict, pre-tax without plan basis, invalid Box 12 letter, deferral without Box 12, HSA without code W, HSA without employer split, stale plan year, missing effective date, and missing withholding order. Each finding carries the line number.

Developers and payroll analysts in the United States who own the deduction-code map inside a payroll or HRIS integration — the CSV that maps internal benefit codes to tax treatment, plan basis and W-2 Box 12 letters. If you ship that file to ADP, Workday, Gusto or an in-house engine, this audits it.

Because nothing here is a syntax error. A deduction row is valid CSV whether the tax flag is right or wrong, so linters and schema validators pass it. A chatbot never sees your map file at all, and generic CSV checkers do not know which W-2 Box 12 letters the IRS accepts or that Roth is after-tax.

Free: every deduction code in the open map is audited against all twelve rules, and each broken line is named with its line number. Nothing is locked, watermarked or time-limited. The full version audits every deduction map in the workspace at once and writes a dated exposure report you keep as the payroll audit trail.

Hand-checking one deduction map against the IRS Box 12 letter list, row by row, is roughly half a day of a payroll analyst's time, and it has to happen again every plan year. If a wrong flag is only caught after the January 31 filing date, the work becomes a W-2c per affected employee plus a re-run of the affected pay periods.