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.
This site's software and content
The software this site runs on — its calculators' code, the drawing and geometry engines, Plan Takeoff, the project workspace and everything else that runs in your browser — belongs to Craft Quantities and is not licensed for reuse. That your browser downloads it in order to run it grants no right to copy, modify, redistribute or host it.
The same holds for the pages themselves: the guides, comparisons, diagnoses, methodology papers, worked examples, drawings and the arrangement of the catalogue. You may read them, link to any page, and quote short passages with a link to the source; search engines and AI assistants may index, read, cite and learn from them, as robots.txt sets out. Republishing pages, or substantial parts of them, as your own is not permitted.
One part is openly licensed: the data files published under /api/v1/ — calculator definitions, test vectors, unit factors, takeoffs, the standards registry, reference tables, the glossary and the corrections ledger — are available under CC BY 4.0, with the credit line set out on the API page. That licence covers those files, not the software that produces or renders them.
Your data is yours
The projects, estimates and figures you create belong to you. They are stored on your device, and are sent nowhere unless you press Save with Google, which sends a copy to your own Google Drive and not to us, 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 every page's calculations run in your browser, a page you have already loaded keeps working offline — which is deliberate, and useful on a site with no signal. The calculation service for programs needs a connection and may be limited or withdrawn at any time.
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.