Terms
These calculators are provided free, as-is, for estimating. They are not a substitute for a professional measurement or a supplier quotation.
Use
You may use these tools for any lawful purpose, personal or commercial, without payment or registration. You may embed a calculator using the snippet provided on its page, provided you do not remove the attribution link.
Accuracy
Calculations are tested, but results depend on the assumptions written on each page — material yields, coverage rates, waste factors and dimensions all vary between products and suppliers. Confirm quantities against the supplier's own guidance before ordering, and add your own margin where the cost of running short is high.
No result here constitutes professional, engineering, construction, financial or legal advice.
Liability
The tools are provided without warranty of any kind. To the extent permitted by law, no liability is accepted for loss arising from use of these calculators, including over-ordering, under-ordering, project delay or cost.
Changes
Tools are corrected and improved without notice; each page shows the date it last changed.