Alex Seote
Built and maintains Rule Calculator
Alex Seote built Rule Calculator and maintains it: 937 pages of arithmetic, 74 of them calculators, each computed from a published formula and published with its derivation and its source.
That is the whole of the claim, and the narrowness is deliberate. The person behind these pages writes and checks the calculators; he is not a structural engineer, a physician or a financial adviser, and no page here pretends otherwise. What the site offers instead of credentials is a formula you can see, a source you can open, and a date saying when it was last looked at.
Formulas and sources last reviewed · How we check
How the numbers are produced
- The number is never written by hand
- Each calculator is one declarative specification — inputs, formula, sources, a worked example — and a fixed evaluator produces every figure from it. Nothing on the site is a number somebody typed into a page, which is why every result can print the arithmetic that made it.
- A formula without a source does not ship
- Every calculator names the body that published the formula it uses: NIST for unit factors, ACI and the Portland Cement Association for concrete, the CDC for body-mass figures, BIPM for time. The build refuses a specification with no source attached.
- Exact and approximate are not allowed to look alike
- An inch is exactly 25.4 mm. An average month is 30.436875 days and is not exact at all. Units carry a flag saying which they are, and the page wording follows the flag rather than the author, so a figure cannot be called exact by accident.
- The checks run on every deploy
- Over a hundred tests run before anything ships, including a set that recomputes results against arithmetic done a second way — geometry against its own formulas, every conversion against the ratio of its two base units, in both directions. A formula that is wrong in a way its own specification agrees with fails there.
How we check describes what the build verifies in detail.
Corrections
A wrong number is a bug, not a difference of opinion, and it is the feedback this site most needs. Every calculator carries a Did this answer your question? control at its foot; answering No records which page the report came from.