Anyone can publish a calculator. The hard part — and the thing we care about — is making sure it gives the right answer, and that the explanation around it is genuinely useful rather than filler. Here is how we do that.
Tested against known answers
Every tool that computes something has a set of fixtures: a list of inputs paired with their verified expected results. For example, the percentage calculator is checked against cases like 15% of 240 = 36. Those fixtures are the single source of truth — they drive three things at once:
- the example the tool loads with;
- the worked example you read in the explanation (it is generated from the fixtures, never hand-typed, so the prose cannot drift from the maths);
- an automated test that re-runs every case and fails loudly if a tool ever stops agreeing with its known answers.
Explanations that actually explain
Each tool page carries a real explanation: what the tool does, the formula or method it uses, a worked example, who it is for, and answers to the questions people actually ask. We write to a fixed content standard and cut anything that adds no information. There are no padded introductions and no invented statistics.
Honest authorship and sourcing
We do not invent authors or credentials. Everything here is published by BOSH Group, a real company. Where a tool makes a claim about money or health, we cite a primary authority — such as the NHS or gov.uk — and link to it.
We hold consequential tools back until they're ready
Tools that touch money or health ("your money or your life" topics) are held to a stricter review and are kept out of search-engine results until a person has reviewed them against our standard. We would rather a page be unlisted than be listed and wrong.
If a tool can't be made fast, accurate and genuinely useful, we don't ship it.
Published by BOSH Group. Last reviewed 30 June 2026.