Sources: the statutory tables behind every figure

Numurio does not estimate from averages. Each market ships a dataset with its own tax year, review date and source list, and every calculator reads from that dataset. The complete list is below — 44 primary sources across eight payroll systems. Where a national revenue body publishes a machine-readable page, that page is the link; where it publishes only a PDF or a Federal Register notice, the notice is the link.

What the sources do not cover

A published table fixes the rates. It does not fix your personal facts: filing status, dependants, pre-tax deductions, a second job, or a local surcharge that only applies in one city. Those inputs are yours to set, and the result moves with them. See methodology for what each engine models exactly, and what it deliberately leaves out.

A link that no longer resolves does not mean the number is wrong — agencies move pages between tax years. The dataset keeps the source label so the rule can still be found by name.