Editorial policy

Editorial Policy

How BuildCalc is made: what we base our numbers on, what we label as estimates, and how we fix mistakes.

Last updated: 10 November 2026.

Sources

Calculator formulas come from two places: manufacturer coverage and yield data — the figures printed on product labels and in manufacturer technical sheets — and standard trade formulas, the area and volume maths every estimator uses (length × width, volume ÷ 27 for cubic yards, and so on). Where a figure depends on the product, the calculator asks for it instead of assuming it: the coverage on the label, the bag yield on the bag, the waste factor for the layout.

No single national number

Coverage varies by brand, finish, colour and surface; bag yields differ by product; prices vary by store and region. So no page on this site states a single national coverage rate or a single national price as a fact. Where a guide gives a typical figure to make the maths concrete, it says it is typical, says what changes it, and tells you to check the label of the product you buy.

Estimates are labelled

Every calculator and every guide carries an estimation disclaimer, and the Disclaimer page explains what the estimates can and cannot do. We never present an estimate as a measurement, and we never present a calculation as professional advice for structural or safety-critical work.

Guides

Each guide is 1,200+ words and works through a real job — a room, a floor, a slab, a bed — step by step, so the reader can see where the number came from. Guides are written to answer the questions people actually ask before buying materials, not to pad a page with keywords. Guides do not repeat each other: each one covers its own job, material and measurements.

Corrections

Mistakes happen, and products change. If a reader reports a wrong number — with the label or source they checked it against — we verify it and fix the page. Corrections are made to the page itself; we do not keep a public corrections log, because the corrected page is the record. Report mistakes on the Contact page.

Independence

No manufacturer or retailer pays us to recommend a product, and no sponsored content is presented as editorial. Some outbound links may be affiliate links — see our Affiliate Disclosure — but affiliate links never change a result, a recommendation, or which products a guide mentions.

No credentials claimed

We are not contractors, engineers or inspectors, and we do not present ourselves as such. Our job is to make published numbers easy to use and honest about their limits — and to tell you when the job needs a professional. Questions about this policy can be sent to hello@buildcalc.com.