This page explains how we build, check and maintain the tools and articles on Ali Tools Express.
Choosing formulas
We use formulas that are published by recognised authorities or in peer-reviewed research, such as World Health Organization classifications for BMI, standard annuity formulas for loans and official conversion factors from the US National Institute of Standards and Technology (NIST). Every tool page names its formula, defines each variable and links to its sources. Where experts disagree, or a formula has known limits, we say so on the page.
Testing
Each formula is implemented as a small, separate piece of code with automated tests. The tests compare our results with published reference values, for example a known monthly payment for a standard mortgage, and with hand-worked examples. Tests run automatically every time the site is rebuilt, and a failing test stops the release.
Units and rounding
Calculations run internally in SI units (metres, kilograms, cubic metres) at full precision. Values are converted for display, and only the final result is rounded. Rounding rules are shown where they matter, for example bag counts always round up.
Writing and review
- Author: content is written by Ali Ahmed unless another author is named on the page.
- Health and finance pages carry a disclaimer, and they are published only after a named, suitably qualified reviewer has checked them. The reviewer’s name appears on the page.
- Translations may be drafted with machine assistance, but they are published only after a fluent speaker has reviewed them and adapted the units, currency, spelling and examples for that audience. Pages without a completed review are not published in that language.
Use of AI tools
Some tool explanations and guides are drafted with the help of AI writing tools. A human editor then checks every statement against the sources cited on the page and against the tool itself, runs the worked examples with real inputs, and rewrites anything that cannot be confirmed. AI output is never used as a source. Health, finance and accounting content is additionally reviewed by a named, qualified specialist before it is published, and every guide shows a short “How we made this guide” note.
Independence
Our tools are free and supported by advertising. Advertisers have no influence over our formulas, results or articles, and we do not accept payment for placement in results.
Updates and corrections
Every page shows a “last updated” date, which changes only when the content changes. If you find an error, tell us. We verify the report, fix confirmed mistakes promptly and, for errors that changed results, add a short note to the page describing the correction.