Transparent calculations

Methodology & 2026 Tax Sources

How PaycheckRadar turns wages and withholding-certificate inputs into a paycheck estimate.

1. Gross pay is normalized

Salary inputs are annual already. Hourly inputs use regular hours, overtime hours and the chosen multiplier, then annualize over 52 weeks. Pay frequency converts annual results back to a paycheck.

2. Federal withholding follows Publication 15-T

For 2020-or-later W-4 inputs, the engine applies the IRS 2026 percentage method with filing status, Step 2(c), Step 3 credits and Step 4 adjustments.

3. FICA is separate

Social Security is calculated at 6.2% up to the 2026 annual wage base of $184,500. Medicare uses 1.45%, with Additional Medicare withholding above the employer withholding threshold.

4. State logic is state-specific

California uses EDD Method B and SDI; New York uses annualized schedules; Illinois, Pennsylvania, Georgia, Arizona and North Carolina each use published state methods. Texas and Florida have no individual state income-tax withholding on wages.

5. Automated regression tests protect the engine

The test suite includes published examples for California, New York State/NYC, Illinois and North Carolina, plus federal-table, Social Security wage-base and reconciliation tests.

Estimator limitation. A real pay stub can differ because of year-to-date caps, supplemental wages, benefits, local rules, reciprocity, special payroll periods and employer configuration.

Primary sources

Tax year 2026. Last reviewed September 27, 2026.