Specific, not generic
We write for someone about to buy materials. That means real numbers, sizes and scenarios, short paragraphs, and examples in both imperial and metric units. We avoid vague advice that does not help you decide how much to buy.
Sourced figures
Every coverage rate, density and pack size in a calculator comes from a manufacturer data sheet, a retailer listing or an industry guide, and we record the source for each one. Where products vary, we use a typical value, say so on the page, and let you change it.
Transparent results
Each result shows the formula and assumptions behind it. Each calculator page explains the method in plain language, the usual waste allowance, common mistakes and what else the job needs.
No made-up prices, experts or reviews
We do not invent prices: costs appear only when you enter your own. We do not use fake experts, credentials or testimonials. Any review of a calculator will be credited to a real, named person.
Safety
We do not give structural, electrical, gas or roofing design advice. Where a job needs a licensed professional, we say so.
Corrections
If you find an error, tell us. We check every report, fix confirmed errors, update the date on the page and note formula changes in the formula changelog.
Advertising
The site has no ads or affiliate links today. If that changes, they will be clearly labeled, never placed above a calculator, and they will never change a result.