How calculators are built and checked
Every Mathulate page follows the same path from a public formula to a tested answer. This page describes that path, and what it does not claim.
Choosing the formula
A calculator starts with a formula that already exists in public. Preferential sources are standards bodies, government guidance, professional associations and peer-reviewed papers. The formula is written as a plain expression that matches the cited source, so a reader can compare the two line by line.
Where public sources disagree, the page says which one it follows and why. Where a source sets thresholds or categories, the thresholds are copied from the source rather than invented.
Writing the page
Each page is written from scratch in plain Canadian English. It names the inputs, shows the formula, works through an example with real numbers, explains the assumptions, and states the limits of the result. Nothing is copied from another calculator site.
Sources
Every calculator lists the sources its formula and thresholds come from, with a link to each one. Sources are linked on the calculator page itself, not in a separate document, so the citation is next to the working it supports.
Worked examples
Each calculator includes a worked example that shows how its formula applies to particular inputs. Automated tests compare selected inputs with expected results. A passing test does not establish correctness for every possible input or individual situation.
Automated tests
Automated tests run calculations with chosen inputs and compare the output to expected values. They also check unit conversions and selected invalid inputs. These checks can catch regressions, but they do not replace independent verification of a formula or professional judgement.
- Expected valueThe cited formula and example provide an expected result for selected inputs.
- Test caseThe inputs and the expected value are added to the calculator's test file.
- Run the suiteEvery calculator is exercised through the real engine, not a stand-in.
- BuildThe static site is built only after the suite and the type check pass.
Review
Sources are provided so readers can check the formula, units, thresholds and limitations. The date on a calculator records a content update. It is not a claim that an independent clinician, financial adviser or other licensed professional reviewed or endorsed the page. For decisions with medical, financial or legal consequences, obtain advice from a qualified professional.
Corrections and how a fix ships
When a mistake is reported, we check the formula against its source and the expected value against the hand calculation. A confirmed error is fixed in the calculator, its worked example and its tests together, so the page, the engine and the suite agree. The corrected page is then rebuilt and redeployed, and its reviewed date is updated.