Calculator quality gate
A calculator is not complete until it has working logic, validation, formula documentation, assumptions, limitations, examples, references where needed, related links, mobile testing, accessibility checks and QA notes.
Source hierarchy
Official agencies, standards bodies, public health authorities, central banks and statistical agencies are preferred for formulas, thresholds and current data. Competitors are used for product benchmarking, not as primary factual sources.
Data freshness
Static formulas, periodically updated datasets and live/API-dependent calculators are tracked separately. Live data is never simulated.