CalcBrook

About CalcBrook

CalcBrook makes free calculators that answer one practical question: how much do I need to buy?

Why we built CalcBrook

Most material calculators online are built for one country. If you are in the UK, you end up converting cubic yards to cubic metres and guessing how many 25 kg bags make up an 80 lb bag. If you are in the US, metric-only tools are just as awkward. CalcBrook works in both: switch between US units (feet, inches, pounds, gallons) and UK metric units (metres, millimetres, kilograms, litres) at any time, and the answer is given in the bag, tin, box and sheet sizes you will actually find in stores on each side of the Atlantic.

How our calculators work

  • Formulas are published. Every calculator explains the maths it uses, with worked examples in US and UK units, so you can check any result by hand.
  • Exact unit conversions. We use the official definitions — for example, 1 ft = 0.3048 m and 1 US gallon = 3.785411784 litres — and only round at the end.
  • Real product sizes. Results are rounded up to whole bags, boxes, tins and sheets, using common retail sizes. Where products differ, you can enter the figure from your own packaging.
  • Tested. The calculation logic is covered by automated tests that check the worked examples on every page.
  • Reviewed. Each page shows when its formulas and figures were last reviewed.

Your privacy

Calculations run entirely in your browser. The numbers you type are not sent to us or stored on our servers. The site is free to use and supported by advertising; see our privacy policy for details.

A note on accuracy

Our results are careful estimates, not professional advice. Product yields and coverage vary between brands, and building codes and regulations differ between places. For structural work, follow your local code or building regulations and consult a qualified professional.

Get in touch

We currently offer 10 home and DIY calculators and are adding more. If you have spotted an error, want a new calculator or have feedback, email us at contact@calcbrook.com or visit our contact page.