| Primary source | How we use it |
|---|---|
| IRS Publication 15-T (2026) irs-15t-2026 | Automated percentage method and W-4 adjustments |
| IRS Publication 15 (2026) irs-15-2026 | FICA, Additional Medicare, and supplemental wages |
| SSA Contribution and Benefit Base ssa-cbb-2026 | 2026 Social Security wage base and rates |
| Florida Department of Revenue: Other Taxes and Fees fl-dor-other-taxes | Florida does not impose personal income tax |
| Florida Constitution, Article VII, Section 5 fl-constitution-art-vii | Constitutional limits concerning tax on the income of natural persons |
| Florida Department of Revenue: Taxes and Fees fl-dor-taxes-fees | Florida-administered sales, corporate, documentary stamp, reemployment and other taxes |
Federal withholding sources
IRS Publication 15-T supplies the percentage-method process and tables used for automated payroll systems. IRS Publication 15 supplies employer guidance for Social Security, Medicare, Additional Medicare and supported supplemental-wage withholding. The Social Security Administration contribution and benefit base material is used to confirm the annual taxable wage ceiling.
Florida sources
The Florida Constitution and Florida Department of Revenue materials support the statement that Florida does not levy individual state income tax and help distinguish that rule from taxes Florida does administer. These sources do not replace federal payroll guidance.
Review and change policy
The active configuration is tax year 2026 and was reviewed August 29, 2026. A new tax year requires a versioned configuration, source review, boundary tests and explicit activation. If a source changes during the year, the affected claim or constant must be reviewed before the site is updated.
Source links can move even when the underlying rule does not. A broken link should be reported through the corrections page; it should not be silently replaced with an unofficial summary.