About and sources

What this site is

Offcut Works is a set of free calculators for UK garden and building jobs, in metres and millimetres. They are meant to help you work out quantities before you buy, and to show the working so you can check it.

How the calculators are built and checked

• The maths behind every calculator is covered by automated tests that compare results with hand-worked examples.
• Where a default value comes from a manufacturer guide, merchant table or official page, the page lists it under "Where the defaults come from".
• Where we could not find a primary source for a default, the page says so under "Defaults we could not confirm from a primary source".
• Board makers and suppliers differ. The guide for the product you buy always takes priority over anything here.

What the calculators do not do

They give estimates for planning and ordering. They do not give structural, legal or building regulations advice. Span tables, manufacturer guidance, your local planning authority and building control come first.

Privacy

The calculations run in your browser and nothing you type is sent anywhere. The pages load fonts from Google Fonts, which is a request to a third party. Read the full privacy policy.

Money

There are no ads or affiliate links on this site at present. If that changes, it will be stated clearly on the pages concerned.

Corrections

If you spot an error or a default that does not match a manufacturer guide, please email [email protected] with the page and the figure, and the source if you have one.