Editorial Policy

Every calculator page explains its task, formulas, assumptions, worked example and limitations. A formula review date is not an expert endorsement. We do not invent professional reviewers or imply personalized financial advice.

Generic arithmetic is separated from country-specific tax or legal rules. A jurisdictional tool must identify its official sources, effective dates and supported cases before publication. Historical guides retained from the earlier website are explicitly marked pending editorial review.

Policy updated: 14 October 2026.