Sources
Tax rates, bands, thresholds, caps and allowances come from official sources: tax authorities, social security agencies, finance ministries and official gazettes. Advisory firms' summaries are used only to cross-check. Each calculator's code lists the source for each figure and when it was checked.
When the current year's figure is not yet published, the page uses the latest official figure and says so. When an official page could not be reached, the figure is cross-checked against more than one reputable source and the page is reviewed again before relying on it.
Testing
Every calculator has automated tests. Where a tax authority publishes worked examples or runs its own calculator, our results are compared with them, for example the German finance ministry's wage tax calculator, the Austrian ministry's gross to net calculator, Canada's published payroll examples and the French URSSAF simulator. The full test suite must pass before any change is published.
Writing
- Pages answer the reader's question first, in plain language, then explain how the result is calculated.
- Every number in the text comes from the calculator code, never typed by hand.
- Each page states its assumptions and limits.
- No invented reviews, ratings, testimonials or user numbers.
Use of AI Tools
Pages are drafted with the help of AI writing tools and then checked. AI never decides a tax figure: rates come from official sources, results come from tested code, and the text quotes that code's output.
Updates and Corrections
Rates are reviewed when governments publish new figures, usually around the start of each tax year. Corrections from readers are checked against the official source and fixed promptly. Write to grosstonetcalculator.info@gmail.com.
Last updated: 2026-11-07.