Terms of Service
You may use the calculators on this site free of charge for personal and commercial project planning. You may link to any page. You may not copy the site's content wholesale, re-host it, or present it as your own.
Last updated: 6 November 2026.
Use of the calculators
Accuracy
Calculators are provided as planning aids. Formulas are documented on each page, but results depend on the measurements you enter, and real projects vary. Always measure twice, confirm quantities with your supplier, and follow the manufacturer's instructions for the materials you buy.
No professional advice
Nothing on this site is professional, structural, electrical, plumbing or legal advice. For work that affects the structure, wiring, plumbing or safety of a home, consult a qualified professional and follow local building regulations.
Availability
The site is provided “as is”. We may change, add or remove calculators at any time. We do not guarantee uninterrupted availability.
Liability
To the fullest extent permitted by law, we are not liable for any loss arising from reliance on calculator results, including over- or under-ordering of materials.