EngineeringFormula

EngineeringFormula

Accuracy & Methodology

How a calculator on this site goes from a formula to a published, tested page - and what to do if you think one of them is wrong.

A calculator that gives a wrong answer is worse than no calculator at all, because a wrong answer that looks confident is easy to trust and hard to catch. Every calculator on this site goes through the same ten-step process before it's published, and the same process again whenever it's corrected.

The process

  • 01Formula identification - the governing equation for a calculator is identified from its standard engineering or physics form, not reconstructed from memory alone.
  • 02Source verification - the formula and any constants it uses (material properties, physical constants, standard conditions) are checked against authoritative references, such as textbooks, engineering standards bodies, and established technical references.
  • 03Dimensional review - every variable's units are checked so the formula is dimensionally consistent, and unit conversions are kept separate from the calculation itself so a unit-handling bug can never silently change a result.
  • 04Implementation - the formula is implemented as a small, isolated, deterministic function. Results are never generated or approximated by an AI model at calculation time - every answer comes from the same formula, computed the same way, every time.
  • 05Known-answer testing - the implementation is checked against worked examples with independently computed expected results, including values pulled from or cross-checked against external references where available.
  • 06Unit conversion testing - every unit a calculator offers is exercised in at least one test, confirming that switching units changes the display, not the underlying physics.
  • 07Boundary testing - inputs at the edges of what's physically valid (zero, negative, and other invalid combinations for that formula) are tested to confirm the calculator rejects them with a clear message instead of returning a nonsensical result.
  • 08Content review - the surrounding explanation, assumptions, limitations, and FAQs are checked for accuracy alongside the formula itself, so the page doesn't just compute correctly but also explains itself correctly.
  • 09Versioning - each calculator page records the date it was last reviewed, so you can see how current the review is.
  • 10Correction process - if an error is reported and confirmed, the formula, its tests, and its explanatory content are corrected together, and the reviewed date is updated.

Content quality checks

  • 01Can a non-expert tell which input values they need and where those values usually come from?
  • 02Does the page explain the practical next step after the number is calculated?
  • 03Are close sibling calculators clearly distinguished so users do not pick the wrong tool?
  • 04Are limitations explicit enough that the calculator is not mistaken for a code-compliant design approval?
  • 05Do related calculators and examples give Google and users a clear path to deeper context?

Indexing review workflow

When Search Console reports a page as crawled but not indexed, the first check is technical: indexability, canonical URL, sitemap inclusion, redirects, and page rendering. If those are clean, the page is reviewed for content usefulness - whether the inputs are understandable, the result is actionable, and the page is sufficiently distinct from similar calculators. Improvements are logged before requesting another crawl.

Reporting a suspected error

If a result looks wrong, the most useful report includes the calculator's URL, the exact values and units you entered, the result you expected, the result you actually got, and - if you have one - a source you're comparing against. The Contact page has a "Report Calculator Error" option set up for exactly this. Every report is checked against the formula and its test cases before any change is made.