Editorial standards
Every calculator on Tool Corner states its method, cites its sources and shows a worked example that has been checked against the live tool. This page explains how that is done, and what we will not do.
Who writes these tools
Tool Corner is written and maintained by its own small editorial team rather than by contributors or syndicated content. Every calculator is built by the same people who write the explanation that sits beneath it, which is deliberate: if the maths cannot be explained plainly, it usually means the model behind it is wrong. We do not publish sponsored calculators, and no tool on the site is written by or paid for by a third party.
Where the formulas come from
Each calculator implements a published, citable method — not an in-house approximation. Financial tools follow the standard amortisation, compounding and tax-band formulas, with rates taken from HMRC and guidance from MoneyHelper and the FCA. Health tools use the established clinical and sports-science equations (Mifflin-St Jeor, Devine, WHO BMI categories) and cite NHS, WHO, CDC or the relevant professional body. Engineering tools use textbook mechanics with SI units throughout. Unit conversions follow the exact factors published by NIST and BIPM. The sources for any given tool are listed at the bottom of that tool’s page — never a generic site-wide block.
How the numbers are checked
Every worked example on the site is computed independently and compared against the live calculator before publication; if the two disagree, one of them is wrong and neither ships until they match. Inputs are tested at their edges — zero, empty, negative and impossible values — so a tool returns a clear message rather than NaN or Infinity. Where a formula has known accuracy limits, those limits are stated on the page in an Assumptions and limitations section rather than left implied.
What we will not do
We do not give financial, medical, legal or structural advice, and no calculator here is a substitute for a professional who can see your actual circumstances. We do not invent author personas or fabricate review credentials to look more authoritative. We do not pad pages with content that does not help — if a tool genuinely does not need a formula section or a worked example, it does not get one.
Review cycle
Tools whose figures change on a schedule — tax bands, VAT rates, statutory thresholds — are reviewed each time the relevant rate changes and at the start of every UK tax year. Everything else is reviewed at least annually. The date at the foot of each page is the date that page was last reviewed, not the date the file was last touched by a build script.
Corrections
If a figure looks wrong, it might be. Every tool page carries a “Report it” link that goes straight to us, and we would rather hear about a rounding discrepancy than not. Corrections to a calculation are made immediately; the review date on the page is updated when they are.