Methodology & Sources
Every figure in the NetPayGuide calculator comes from a primary government source — never a third-party aggregator, never an estimate. Below is the full citation list for the 2026 tax year. When a state legislature or the IRS releases new numbers, this page updates within the same week.
Federal sources
- IRS Publication 15-T — Federal Income Tax Withholding Methods
The primary federal withholding reference for employers. Used for percentage-method withholding tables.
- IRS Revenue Procedure 2025-11 — 2026 inflation adjustments
2026 tax brackets and standard deductions for single, married filing jointly, head of household, and married filing separately.
- IRS Topic 751 — Social Security & Medicare Withholding
FICA rates, additional Medicare thresholds ($200k single / $250k MFJ / $125k MFS).
- SSA Contribution and Benefit Base
2026 Social Security wage base ($176,100). Updated annually by SSA.
State sources
- California — Franchise Tax Board 2026 Rate Schedules
CA brackets (1%–13.3%) plus SDI rate (1.2%) and SDI wage base ($153,164) from EDD.
- Texas — Comptroller of Public Accounts
No state income tax (Texas Constitution, Article VIII).
- Florida — Department of Revenue
No state income tax (Florida Constitution, Article VII §5).
- New York — Department of Taxation and Finance
NYS brackets (4%–10.9%). NYC and Yonkers local taxes are not currently included in the calculator.
- Illinois — Department of Revenue
Flat 4.95% rate (35 ILCS 5/201(b)(5.8)) plus $2,625 personal exemption.
More states ship over time. If you don't see your state listed here, the calculator falls back to federal-only withholding (which over-states take-home for states with income tax).
How withholding is calculated
NetPayGuide uses the IRS percentage-method tables (Pub 15-T) for federal withholding. Pay frequencies map to annualized brackets, then back to the pay-period figure. Pre-tax deductions reduce taxable wages before brackets are applied; post-tax deductions (Roth 401(k), garnishments) reduce net pay after withholding.
FICA is computed at the federal statutory rates: 6.2% Social Security (capped at the SSA wage base) plus 1.45% Medicare on all wages, with the 0.9% Additional Medicare Tax kicking in above the IRS thresholds.
State income tax follows each state's published bracket schedule for the current tax year, applied to state taxable wages (which may differ from federal taxable wages depending on the state's treatment of pre-tax deductions and standard deductions).
What we don't calculate
- Self-employment tax and quarterly estimated tax (W-2 employees only)
- NYC, Yonkers, or other local income taxes (NY state tax only)
- Tax credits applied at filing (EITC, Child Tax Credit, etc.)
- Garnishments, child support orders, or other court-ordered withholdings
- Employer-paid benefits (the calculator estimates employee paycheck only)
Updates & corrections
The IRS typically releases the next year's inflation adjustments in late October or early November. State revenue departments follow a similar cadence. NetPayGuide updates within one week of each release; the changelog lives in the source repository.
Found a discrepancy? Email [email protected] with the figure, the source you're comparing against, and the state/scenario in question.
This page is educational reference, not personalized tax advice. For decisions that materially affect your filing, consult a licensed tax professional or your payroll department.