Data operations

Tax data status

Every rule set has a tax year, review date, coverage boundary, and source trail. Recurring checks look for changes; public numbers change only after the source and arithmetic are verified together.

Automatic review, controlled release

A weekly review looks for candidate changes in IRS, SSA, state-tax, and processor materials: a newer tax year, certified rate trigger, amended guidance, midyear change, or revised public pricing. A candidate is not released merely because it appears in a secondary compilation. The applicable year and effective date, source trail, affected value, and boundary tests must be reviewed together before publication.

What “state coverage” means

The state calculator covers the published individual-income-tax rate schedule for a single or married-joint return when the user supplies state taxable income. It does not determine residency, create the state taxable-income line, or calculate credits, part-year or nonresident filing, multistate allocation, alternative taxes, entity-level taxes, or city and county tax. Coverage is limited to the 50 states and Washington, D.C.; US territories and tax systems outside the United States are not modeled.

State source trail

The dated Tax Foundation compilation is a secondary discovery source. The USAGov and Federation of Tax Administrators directories lead to state agencies; the selected state’s current form and instructions remain controlling for filing.

• Tax Foundation — dated 2026 rate compilation used for discovery (secondary source)
• USAGov — official directory for controlling state tax forms and instructions
• Federation of Tax Administrators — state-agency research directory

Jurisdiction evidence matrix

The agency destinations below were checked against the Federation of Tax Administrators member directory on 2026-07-28. Every current entry is marked Official agency directory verified. This routes you to the controlling agency; it does not claim that the application’s full 2026 schedule has been primary-confirmed. No jurisdiction will receive that status until a controlling official source confirms both the tax year and effective date.

Found a discrepancy? Use the process described in the editorial and corrections policy. A material correction receives a new review date and a regression test.