Concrete Calculator
Estimate concrete volume for a simple rectangular slab by entering length, width and depth. The calculator also adds a 5% allowance for waste.
Your result will appear here.
How to use the concrete calculator
Measure the rectangular slab’s length, width and thickness in the same unit. Choose metres, feet or inches, then calculate the volume. The optional 5% allowance helps account for small losses and uneven surfaces.
Formula used
Volume = Length × Width × Depth. All measurements are converted to metres before the volume is calculated in cubic metres.
Before ordering concrete
This tool is a basic estimate for a rectangular slab. It does not account for complex shapes, footings, slopes, reinforcement displacement, site conditions or supplier minimum loads. Have construction drawings and quantities checked by a qualified professional.
Frequently asked questions
Why add a waste allowance? Real projects can need extra material because of spillage, uneven ground and minor measurement differences. The 5% allowance is only a planning assumption.
Can I use it for a circular footing? Not directly. This version is only for rectangular slab dimensions.
Construction disclaimer: This is an approximate material estimator, not an engineering design or structural specification.