Concrete Calculator We recommend you add at least 1/4 meter to your calculation. Slabs, Square Footings, or Walls length footinchyardmetercentimeter width footinchyardmetercentimeter thickness or height footinchyardmetercentimeter quantity Hole, Column, or Round Footings diameter footinchyardmetercentimeter depth or height footinchyardmetercentimeter quantity Circular Slab or Tube outer diameter footinchyardmetercentimeter inner diameter footinchyardmetercentimeter length or height footinchyardmetercentimeter quantity powered by calculator.net This tool is to be used as a guide only. GAL will not be responsible for any measurements or volumes ordered.