About
About Checked Math
What Checked Math is, what every calculator page shows you, and the rules the site follows when it publishes a tool.
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What this site is
Checked Math is a small library of focused calculators. Each tool answers one kind of question and shows how it reached the result instead of returning a bare number.
The name reflects the product design: formulas, substituted values, assumptions and calculation steps are shown so readers can check the work themselves.
What every calculator page includes
- The inputs it needs and the unit each one expects.
- The formula, the substituted values and the calculation steps.
- Worked examples you can reproduce by hand.
- What the calculator does not do, common mistakes, and edge cases such as zero or negative values.
What the site avoids
- Silent defaults that change a result without telling you.
- Many near-identical pages that differ only by a word or a number.
- Presenting an estimate, a model or a planning assumption as an exact fact.
- Publishing a calculator before its formula, examples and edge cases have been checked.
How the calculators are maintained
Each formula has a version and is tested against worked examples and boundary values, including zero, negative and very small inputs. When an error is reported and reproduced, the formula, its tests and the explanation on the page are corrected together, as described in the corrections policy.