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How a calculator is built
- We start from a real question people ask, such as how many gallons of paint a room needs.
- We collect the published figures that answer it: manufacturer coverage rates, product data and widely used industry rules of thumb.
- We write the formula, then work it by hand with sample numbers and compare the result with manufacturer calculators where they exist.
- We publish the formula, the default assumptions and the sources on the calculator page.
Sources we use
We prefer primary sources: manufacturers, product labels and technical data sheets. When we rely on an industry rule of thumb, we say so. Every calculator lists its sources at the bottom of the page.
Reviews and updates
Each calculator shows the date it was last reviewed. We review calculators when manufacturers change their published figures, when readers report a problem, and at least once a year.
Corrections
If you find a mistake, email [email protected] with the page and the numbers you used. We check every report and update the page and its review date when a correction is needed.
Use of AI tools
We may use AI tools to help with research and first drafts of explanations. A person checks every number, formula and claim against its source before it is published.
Independence
Matholio may show advertising. Advertisers do not review, influence or pay for calculator results or recommendations.
Limits of an estimate
Calculators give planning estimates. Product labels, manufacturer instructions and local building codes always take priority over a calculator result.