Sources and methodology
PaycheckIndex uses 2026 federal withholding schedules, payroll tax constants, and primary government sources to produce planning estimates. State and local rules should be verified before real payroll decisions.
IRS Publication 15-T - Federal Income Tax Withholding Methods
IRS Publication 509 - Tax Calendars
IRS Publication 15
IRS Publication 15-A
IRS Publication 505
IRS estimated tax FAQ
IRS Topic 757 - Forms 941 and 944 deposits
IRS Form 941 information
IRS 2026 tax inflation adjustment release
IRS qualified overtime deduction FAQ
26 USC 225 - Qualified overtime compensation deduction
SSA contribution and benefit base
US DOL state minimum wage laws
US DOL overtime guidance
US DOL last paycheck guidance
29 CFR Part 778 overtime compensation rules
California DLSE final pay guidance
California DLSE payday FAQ
Alaska state tax facts
Alaska Department of Labor 2026 unemployment insurance rates
Florida Department of Revenue personal income tax FAQ
Nevada Department of Taxation income tax overview
New Hampshire Department of Revenue Administration tax overview
South Dakota Department of Revenue individual tax overview
Tennessee Department of Revenue withholding guidance
Texas Comptroller personal income tax overview
Washington Department of Revenue income tax forms
Washington Paid Leave and WA Cares premium estimator
WA Cares employer premium guidance
WA Cares exemptions
State of Wyoming overview
Wyoming unemployment tax rates
SBA business management guidance