Wiki Design Principles

சுருக்கம்

This wiki documents the methodology behind every calculator on everycalc. Each article explains what formula is used, where it comes from, what assumptions are made, and how we verify accuracy against official sources.

Why this exists

Every calculator on everycalc is built using authoritative sources — gov.uk for UK tax, HMRC for National Insurance thresholds, WHO for health metrics, and peer-reviewed research for fitness formulas. But without documentation, users have no way to verify our calculations or understand our assumptions.

This wiki solves three problems:

1. Trust — users can see exactly how results are calculated and check our sources
2. Accuracy — documenting methodology forces us to verify every constant and formula
3. Maintenance — when tax rates change each April, we know exactly which articles and constants to update

Article structure

Every wiki entry follows the same template:

1. Summary — what the calculator does, in 50 words
2. How it works — the methodology in plain English
3. The formula — the mathematical formula with a variable legend
4. Worked example — step-by-step calculation with real numbers
5. Inputs explained — what each input means, where to find the real value
6. Outputs explained — what each result means in context
7. Assumptions & limitations — what the calculator does NOT cover
8. Verification — test cases checked against official tools, with dates

Source types

Every article must cite at least one authoritative source. Sources are classified by type:

Verification standards

• Financial calculators must be verified against the official government calculator (e.g., gov.uk SDLT calculator, HMRC tax calculator)
• Health calculators must cite the original research paper or clinical guideline defining the formula
• All calculators must include an accounting identity test in their unit test suite (e.g., gross = net + tax + NI + pension)
• Verification dates are tracked — articles older than 6 months show an amber warning badge

Quality gate

A build-time script checks that every calculator in nav.ts has a corresponding wiki entry. Missing entries generate warnings (eventually, build failures).

How to contribute a new article

1. Create a new .mdx file in src/content/wiki/
2. Add the required frontmatter (title, description, sources, etc.)
3. Follow the article template structure above
4. Add the calculator path → wiki slug mapping in src/data/wikiSlugs.ts
5. Run npm run build to validate the frontmatter schema
6. The article will automatically appear on the wiki hub page