Useful, testable, and honest by design.

Our standard is simple: explain what the calculation does, expose material assumptions, and never present an estimate as a guaranteed outcome.

Calculator development

We define the question, select a recognized mathematical method, implement the calculation, and test ordinary cases, boundary conditions, and reconciliation totals. Where industry practice varies, the calculator provides a user-controlled assumption or clearly states the limitation.

Sources

Priority is given to primary and authoritative sources such as government agencies, regulators, standards bodies, and official documentation. External sources explain the governing method or subject; they do not replace the user’s entered figures. Source review dates appear on applicable calculator pages.

Writing and review

Explanations are written for people making real decisions. We avoid manufactured certainty, hidden assumptions, unsupported claims, and content added solely to reach a word count. Material calculator changes are checked against the formula and automated test suite before publication.

Use of automation

Automation may assist drafting, code review, or consistency checks. Published calculations remain deterministic code, and the final page is reviewed for mathematical coherence, clarity, and accurate limitations. Automation is never presented as a licensed professional.

Updates and corrections

We update a page when its formula, assumptions, source guidance, or functionality materially changes. Styling changes alone do not make old guidance new. If you find an error, follow our corrections process. For the exact mathematical conventions, read our methodology.