Practical guide
How to Calculate Concrete Volume
Concrete is normally ordered by volume in cubic metres. The basic calculation is length multiplied by width multiplied by depth, with every measurement converted to metres first.
Fact checked and updated 13 September 2026
Convert depth before multiplying
A depth of 100 mm is 0.1 m, not 100 m. Multiply the finished length, width and converted depth to get cubic metres. Break irregular shapes into smaller rectangles and add their volumes.
Separate measured and ordered volume
The measured volume is the geometric requirement. The order quantity can include an allowance for uneven excavation, spillage and level variations. Do not use the allowance to hide uncertain measurements.
Check the specification
Volume does not tell you the required concrete strength, reinforcement, curing method or structural thickness. Obtain the correct specification from the plan, engineer or responsible professional before ordering.
Use the related calculators
Apply the explanation above with your own figures. Open a calculator below, check every input and review the result assumptions before making a decision.
Official source checked
This guide was checked against Cement and Concrete South Africa. Rules, rates and institutional requirements can change, so confirm time-sensitive information at the official source.