Terms of use

Use of the site

You may use the calculators and tools freely, for personal or commercial work, including in documents you produce for clients. No attribution is required, though it is welcome.

You may not attempt to disrupt the site, misrepresent its output as certified engineering, or present it as your own product.

Your data is yours

The projects, estimates and figures you create belong to you. They are stored on your device and never transmitted, so no licence to them is granted or needed. Nothing here claims any rights over what you produce.

Standards and codes referenced

Standards named on this site — ACI, IRC, NEC, IPC, ASHRAE, Eurocode, AS/NZS, BS and others — are the property of their publishers. They are cited so a figure can be traced to its authority. They are not reproduced here, and citation implies no endorsement by, or affiliation with, the publishing body.

Where a calculation follows a published method, the citation identifies the method. It does not certify compliance: only the authority having jurisdiction can do that.

Availability

The site is offered without any guarantee of availability or of continued publication. Because everything runs in your browser, a page you have already loaded keeps working offline — which is deliberate, and useful on a site with no signal.

Changes

Calculators are revised as standards change and errors are found. Each carries a version and a changelog so a figure you used previously can be traced. These terms may change; the current version is always the one on this page.