Calculator and Content Methodology
Our method prioritises transparent formulas, dated rules, authoritative sources, reproducible tests and clear limitations.
Evidence hierarchy
We prefer legislation, GOV.UK, HM Revenue & Customs, the Department for Work and Pensions, regulators, the Bank of England and official statistics. Government-backed guidance may be used to explain decisions in plain English.
Formula governance
Each calculator has a written method, source list, known-answer tests, boundary tests and a named update owner. Changing rates are versioned by effective date. A successful automated test does not replace subject-matter review.
Search and AI visibility
Pages are written for humans first, with direct answers, semantic headings, extractable tables, visible sources and structured data that matches the page. We do not create doorway pages for word-order, amount or place-name variations.
Publication gates
The preview is globally noindex. Production indexing requires source, formula, accessibility, duplicate-intent, structured-data, editorial and applicable compliance gates to pass.