SalarySplitHub calculation methodology

What the calculator estimates

The calculator estimates annual federal income-tax liability, employee Social Security and Medicare taxes, supported state income-tax liability, supported mandatory employee payroll deductions, and user-entered qualified pre-tax deductions. It then divides annual net pay by 12, 24, 26, or 52. It does not reproduce an employer's pay-period withholding tables.

Calculation order

1. Subtract entered Traditional 401(k), qualified HSA payroll contributions, and qualified pre-tax health premiums from federal income-tax wages.
2. Apply the 2026 federal standard deduction and progressive brackets to estimated taxable income.
3. Calculate Social Security at 6.2% up to the 2026 $184,500 wage base and Medicare at 1.45%. Traditional 401(k) deferrals remain FICA wages; the model assumes entered HSA and health amounts are qualified payroll salary reductions excluded from FICA wages.
4. Apply Additional Medicare withholding at 0.9% above $200,000 of Medicare wages. Final return liability uses filing-status thresholds and may differ, especially for married filers.
5. Apply the state's represented brackets, rate, deduction or exemption, and conformance flags. Add supported local tax only when explicitly selected.
6. Add supported employee payroll deductions. California SDI is modeled at the official 2026 rate of 1.3% with no wage limit, using qualified-benefit wage exclusions.

Rounding

Tax components are rounded to cents after each component calculation. Displayed page values may be rounded to whole dollars. Pay-frequency values divide the annual result; they do not simulate payroll-period rounding.

Important limitations

• No tax credits, dependents, itemized deductions, AMT, capital gains, self-employment tax, bonuses, tips, stock compensation, or other income.
• No nonresident, part-year resident, reciprocity, multi-job, or multiple-employer Social Security adjustments.
• Most city, county, school-district, paid-leave, unemployment, and occupational taxes are not included. New York City is optional; California SDI is included.
• HSA and health inputs are assumed to be eligible qualified payroll deductions. Direct HSA contributions and post-tax premiums can receive different payroll treatment.
• State agencies often publish final indexed schedules after federal figures. A state page's source block identifies its source year; a 2025 schedule used in a 2026 planning estimate is not represented as confirmed 2026 law.

Official primary sources

• IRS Revenue Procedure 2025-32 — 2026 federal brackets and standard deduction.
• Social Security Administration contribution and benefit base — 2026 wage base and rates.
• IRS Topic No. 751 and Publication 15-B — payroll-tax and qualified-benefit treatment.
• California EDD taxable wages and SDI — 2026 1.3% SDI rate and no wage limit.

Review policy

Federal and supported payroll figures are reviewed when agencies release annual guidance. State schedules are checked against linked tax-agency material and each calculator shows a review date and available source year. Corrections with an official publication can be sent through the contact page. SalarySplitHub is independent and is not affiliated with a tax agency.