Disclaimer

Everything on BuildCalc is an estimate. Read this page before you buy materials or start a job.

Last updated: 10 November 2026.

Results are estimates, not measurements

Every calculator result and every quantity in every guide on this site is an estimate. Coverage, yield and quantities vary by brand, region and surface condition, and waste varies with the job. A gallon of paint that covers 400 square feet on smooth, primed drywall may cover far less on rough, unprimed or previously painted surfaces. A bag of concrete yields what its label says it yields — and bag yields differ by product and bag size. No page on this site states a single national coverage rate or a single national price as a fact, because no such number exists.

Prices vary by brand, region and store

Prices vary by store and region, and they change over time. Where a guide discusses cost, it tells you to check the price at the store you will buy from. Never treat a price on this site — or a price quoted in a guide — as a quotation.

Verify with the product label and a professional

Before you buy, check the coverage, yield, mixing and safety instructions on the label of the product you actually buy — the label is the authority, not this site. Before you build, measure twice. And for structural or safety-critical work — load-bearing slabs, retaining walls, foundations, anything involving gas, electricity or water supply — ask a qualified professional who can see the job. BuildCalc is not a substitute for professional advice, a structural engineer, or a building inspector, and nothing on this site should be treated as one.

No liability for project outcomes

We are not liable for over-ordering, under-ordering, wasted material, project delays, cost overruns, or any damage or injury arising from using the estimates on this site. If a calculator is wrong, tell us on the Contact page and we will fix it — that is the remedy we offer.

Accuracy

We check our figures against manufacturer coverage data and standard trade formulas, and we correct mistakes when they are reported. But products change, labels change, and mistakes happen. If a number on this site disagrees with the label on the product you bought, trust the label.

Questions about this disclaimer can be sent to hello@buildcalc.com.