How we calculate and check every number

Money pages are only useful if the numbers are right. This is how we make sure they are.

1. Rules come from official sources only

Tax brackets, deductions and thresholds come from the IRS, the Social Security Administration, state revenue departments, HMRC, the CRA, the ATO, the German Federal Ministry of Finance and the law texts on gesetze-im-internet.de, and the labour laws of each Gulf country. Reference rates come from Freddie Mac, the Bank of England, the Bank of Canada, the Reserve Bank of Australia and the central-bank currency pegs. See every link on the sources page.

2. Rules are data, not code

Each rule set (for example "Texas, tax year 2026") is stored once with its source URL and check date. The same data produces the example tables on each page and the calculator in your browser, so the two cannot disagree.

3. A person approves every change

A scheduled job compares the official pages with the live rules. When something changes, the difference goes to a review queue and only goes live after a person approves it.

4. Calculators are tested against official examples

Each engine is checked against worked examples published by the authorities and against independent calculations. The browser and server versions of every engine are tested against each other on thousands of inputs.

5. What the calculators do not include

Paycheck calculators estimate the tax for a full year with standard deductions. They do not include every credit, itemized deductions, bonuses taxed at supplemental rates or local taxes outside the cities listed. Germany is in beta and covers tax classes I to IV. Always check your payslip, your tax return or a qualified adviser before making decisions.