Official U.S. Tax Sources
Primary federal references for the U.S. hub and future calculator validation.
Links checked 8 October 2026 · U.S. calculators not yet released
Federal source registry
| Authority | Official resource | Intended scope |
|---|---|---|
| Internal Revenue Service | 2026 tax inflation adjustments | Federal brackets, deductions and selected credits |
| Internal Revenue Service | Publication 15-T: 2026 withholding methods | Federal paycheck withholding and W-4 methods |
| Internal Revenue Service | Credits and deductions | Eligibility and federal credit guidance |
| Social Security Administration | Contribution and benefit base | Social Security wage base |
How sources will be applied
A source link alone does not validate a tax engine. Each released calculator needs a year-specific rule package, calculation tests, boundary tests and review of exceptions. Federal withholding uses different guidance from annual income tax; Social Security and Medicare have their own payroll rules.
State and local sources
No state package is published yet. Before a state calculator launches, Taxliva must cite that state’s revenue agency and any relevant municipal authority. Local sales and property tax figures require current locality-level data; the hub does not guess rates from a ZIP code.
Read the methodology and limitations or return to the U.S. hub.