How the 2026 paycheck estimate works

Included in MVP

Federal income tax withholding, Social Security, Medicare, Additional Medicare, pay frequency, salary/hourly/bonus inputs, filing status, W-4 Step 3, Step 4(a), Step 4(b), Step 4(c), pre-tax deductions, post-tax deductions, and priority state estimates.

How formulas are checked

Tax formulas are implemented in versioned source code and covered by automated tests for representative calculation scenarios. Those tests help detect software regressions, but they do not prove that every payroll situation is covered and do not constitute review by a CPA, enrolled agent, attorney, or payroll professional.

Professional review status

PaycheckDB does not currently identify a qualified tax or payroll professional as a reviewer of these calculations. Official source links and internal editorial checks should not be interpreted as professional certification or endorsement.

Important limits

This is not a final tax return calculator. It does not cover every employer benefit, garnishment, local payroll rule, nonresident allocation, multi-state work arrangement, tipped wage rule, pre-2020 W-4 bridge, or special industry rule. Results are estimates and not tax advice.

Versioning

Federal and FICA data are stored separately from calculation logic. State support levels are visible on each page, so a basic state estimate is not presented as a complete payroll engine. Formulas, tests, and page labels must be rechecked whenever the IRS, SSA, or a state agency changes a table, threshold, form, or instruction.

Editorially updated: 2026-07-20.