Concrete Wall Calculator

About Concrete Wall Calculator

Concrete Wall Calculator sizes a poured concrete wall from its length, height and thickness. Because the tool takes three dimensions in any orientation, enter wall length as the length, wall height as the width, and wall thickness as the depth. A 10 m wall at 2 m high and 200 mm thick holds 4 m3, or 4.4 m3 with a 10 percent waste allowance. Thickness drives the cost here more than anything else: taking the same wall from 200 mm to 250 mm adds a full cubic metre. Wall pours are less forgiving than slabs because formwork deflects slightly under the pressure of wet concrete, which quietly increases the real volume, so keeping the waste allowance at 10 to 15 percent is sensible rather than trimming it to 5. For retaining walls, the thickness, reinforcement and any base or toe are engineering decisions that come from a design, not from a rule of thumb, and the toe should be calculated as a separate footing run and added to the wall volume.

How to use Concrete Wall Calculator

  1. Choose metric or imperial input
  2. Enter length, width, and depth of your slab
  3. See volume and bag count in both metric and imperial instantly

Frequently Asked Questions

How do I calculate concrete for a wall?
Multiply wall length by wall height by wall thickness. A 10 m wall at 2 m high and 200 mm thick is 10 x 2 x 0.2 = 4 m3. In the calculator, enter length as length, height as width and thickness as depth, since the maths is the same for any rectangular volume.
How thick should a poured concrete wall be?
Non structural garden walls are commonly 150 to 200 mm. Structural and retaining walls are sized by an engineer based on the retained height, soil type and drainage, and are frequently 200 to 300 mm with reinforcement. Do not estimate the thickness of a retaining wall.
Do I subtract openings for doors or windows?
Yes. Calculate the full wall volume first, then calculate each opening as its own rectangle using the same wall thickness and subtract those volumes. Openings in a thick wall remove a surprising amount of concrete.
How much waste should I allow on a wall pour?
Ten to 15 percent. Formwork flexes under the pressure of wet concrete, so the finished wall is usually slightly thicker than the nominal dimension, and a wall pour that runs short leaves a visible cold joint across the face.
Does this include the footing under the wall?
No. The footing or base is a separate pour with its own width and depth. Calculate it as a footing run using the trench dimensions, then add that volume to the wall volume for your total order.

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