Salary, contributions, tax thresholds: calculators kept current with the rates actually in force, citing their sources and explaining their results. No account to create, no data sent — everything is computed in your browser.
Each one applies the official texts in force and shows its working rather than just a figure.
The reference values feeding every tool on the site. Many online calculators still run on last year's rates.
Three principles, which also explain why some calculations are deliberately refused rather than approximated.