Editorial Policy

This page explains how our content is written, checked and updated, and where we stand on originality and advertising.

Original and independently written

Our calculator explanations, formula notes and guides are written in-house. We do not copy or stitch together content from other sites. We consult published standards and literature to establish formulas, but the explanations, examples and conclusions are our own.

Sources for formulas and standards

Every calculator states its formula in the “How it works” section. Common sources include:

• Health: WHO BMI bands, Mifflin-St Jeor for BMR, US Navy / US Army body-fat equations, MDRD for GFR;
• Finance: standard amortization (annuity) payments, compound interest, present and future value;
• Math: standard geometric and statistical definitions.

Where authorities differ (for example Chinese versus WHO BMI cut-offs), the page states which standard is used.

Review process

1. Once a formula is fixed, the implementation is tested against edge cases (zero, negatives, very large values, empty input);
2. Calculation logic has automated tests that run at build time;
3. Chinese and English versions are checked line by line to prevent translation drift;
4. Health and finance pages state their limitations and the “not advice” notice explicitly.

Tools and human judgement

We use software tools to help draft, typeset and proofread, and automated tests to verify calculations. Topic selection, formula choice, wording and final publication are decided by an editor, who is accountable for them. We do not mass-produce pages with no substantive content.

Updates and corrections

When a formula or standard changes, or a valid correction arrives, we update the page and note the revision date. If you spot a problem, please contact us with the page URL, your inputs and a reference where possible.

Advertising independence

The site is funded by advertising, but advertising does not influence content. We do not change results or reviews in exchange for ad spend, and we do not disguise ads as editorial content. Ad units are visually separated from the article body.

Content boundaries

We do not publish medical diagnoses, personalised investment advice, legal opinions or misleading material, and we do not publish infringing, hateful, violent or adult content.