Terms of use

You may use the calculators and reference tables freely for personal and commercial estimating, and you may quote small excerpts with attribution and a link. You may not scrape, republish, or redistribute substantial portions of the site's content or data tables without written permission.

Content is provided "as is." We work hard to keep formulas correct and data current, but we make no warranty of accuracy, completeness, or fitness for a particular purpose, and we accept no liability for losses arising from use of the site — including ordering errors. Densities, prices and coverage rates vary by region, supplier and product; the numbers on your delivery ticket govern.

We may update these terms as the site evolves; the effective date above will change accordingly. Continued use after an update constitutes acceptance.