Calterix methodology.
How each calculation is built, tested and kept up to date.
How we build each calculation
- We define the rule from a standard formula, an official rule or a widely accepted method.
- We write the math as a pure function, with no side effects.
- We verify it against independently worked examples.
- We publish it with the formula and source on the page itself.
Official figures and rates
Most calculators use standard formulas that do not change, such as BMI, percentages, loan payments and compound interest. When a page relies on an official figure, such as a published guideline or a government threshold, it names the source and the year used, and the update date appears at the top. Rates in examples are examples: always enter the rate from your own offer.
Professional review
Health and finance pages have a field for review by a qualified professional. Until a reviewer is named on a page, it shows "to be assigned".
Privacy of your numbers
The numbers you type stay in your browser. Some shareable links store the values in the URL itself, which exists only on your device until you send it to someone. More detail is on the privacy page.