Concrete, Brick & Masonry calculator
Concrete Calculator
Calculate concrete volume for rectangular pours from length, width, depth and a practical ordering allowance.
Calculate concrete volume for rectangular pours from length, width, depth and a practical ordering allowance. Use finished project dimensions and product-specific data where available rather than generic defaults. The most sensitive assumption here is true pour dimensions. General concrete pours can vary from drawings because bases and formwork are not perfectly uniform. A modest ordering allowance reduces the risk of a short pour.
What you need to enter
The Concrete Calculator uses the following project information to calculate the result.
- Length
- Width
- Depth / thickness
- Extra allowance (%)
Calculator result
Concrete volume in m³ / yd³
How the Concrete Calculator works
Core method: shape volume × allowance. On the Concrete Calculator, this relationship is applied specifically to concrete volume for rectangular pours such as pads, bases and slabs. Compatible measurements are converted to a common internal unit before calculation, then the result is returned in the selected unit system. The main variable to verify is true pour dimensions.
Concrete Calculator worked example
Concrete Calculator example: a rectangular base 4.8 m × 3.2 m × 120 mm requires about 1.84 m³ before allowance. Adding 7% takes the planning order to roughly 1.97 m³, subject to site tolerances and supplier load sizes. Before relying on that figure, check true pour dimensions; the final decision should also follow the actual product or project specification.
Important calculation assumptions
For concrete volume for rectangular pours such as pads, bases and slabs, general concrete pours can vary from drawings because bases and formwork are not perfectly uniform. A modest ordering allowance reduces the risk of a short pour.
Frequently asked questions
What should I write down before calculating with the Concrete Calculator?
Before calculating concrete volume for rectangular pours such as pads, bases and slabs, measure the finished pour dimensions, including the real depth. For excavations, check several points because overbreak can increase volume. Avoid substituting an average value where the actual project figure is known.
How sensitive is the Concrete Calculator result to true pour dimensions?
A sensible Concrete Calculator result depends on getting true pour dimensions right. General concrete pours can vary from drawings because bases and formwork are not perfectly uniform. A modest ordering allowance reduces the risk of a short pour.
What should I check before buying from the Concrete Calculator result?
For the Concrete Calculator, treat the output as a decision aid rather than an isolated number. Use the volume as a bulk-order starting point and discuss load increments with the supplier. A small allowance is normally sensible because real pours are rarely perfectly dimensioned.