About Abacurio & Methodology
Abacurio is a free collection of calculators, unit tools and guides in 16 languages, including income-tax calculators written for 25 countries. Every result shows how it was reached.
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Why this site exists
Many calculators give you a number and nothing else. We think you should be able to see the formula, the assumptions and the steps, so you can trust the result or spot when your situation is different. Abacurio is built and maintained by an independent developer and is free to use, with no sign-up.
How calculators are built
Each calculator uses a published, standard formula (for example, the amortization formula for loans or the Mifflin–St Jeor and similar equations for health tools). The page explains the formula in words, lists the inputs, and shows the result together with the intermediate steps. Calculations run in your browser.
How tax calculators are built
Each country has its own calculator, written for that country's rules: income-tax bands, allowances, social-insurance contributions and the main credits or deductions. We take the rules from the official tax authority or legislation of that country, state the tax year used, and show the date they were last checked. A note on each page lists what is simplified or not included, such as some local taxes, special regimes or individual circumstances.
Corrections
If a figure looks wrong, tell us the page, your inputs, the result you expected and a link to the official source. We review every report and publish a fix when it is confirmed.
How the site is funded
Advertising pays for hosting and development. Ads are always separate from calculator results, and do not influence them. Pages designed for downloading offline copies carry more ads and are kept out of search results.