Methodology guides

Guides filed under Methodology on PaycheckSum: payroll taxes explained from primary sources, with the calculator engines behind every figure.

• The paycheck engine

  Pub. 15-T federal withholding, annualized state tax, cumulative FICA, §224 flow-through, state data status

  Methodology · Methodology · Paychecks, Federal withholding, FICA, State tax

  Published October 26, 2026

• The employer-cost engine

  SUTA rates, FUTA credit status, workers' comp ranges, benefits assumptions

  Methodology · Methodology · Employer cost, FUTA, SUTA, Workers' comp

  Published October 26, 2026

• The self-employment engine

  SE tax, half-SE deduction, simplified QBI, quarterly installments

  Methodology · Methodology · Self-employment tax, 1099, Quarterly estimates, QBI deduction

  Published October 26, 2026