Using the Concrete Calculator
Length and width are in meters, while depth is in centimeters. The calculation converts depth to meters before multiplying. The allowance is applied to the whole volume; density affects the mass result but does not affect cubic meters or cubic yards.
Worked example
Use the example inputs below to reproduce this result. These are the form's starting values, not recommended targets. Changing your inputs updates your result above; this worked example stays fixed for comparison. Results are rounded for display.
Example inputs
- Length (m)
- 5
- Width (m)
- 4
- Depth (cm)
- 10
- Extra allowance (%)
- 10
- Bulk density (kg/m³)
- 2400
Example result
- Volume (m³)
- 2.2
- Volume (cubic yards)
- 2.8774914
- Estimated mass (kg)
- 5,280
Method and assumptions
Length × width × depth, plus the selected allowance. Density is user supplied and varies with material and moisture.
Turn an estimate into an order
A geometric quantity is a starting point for purchasing. Check whether the supplier sells by bag, box, mass or bulk volume, and use the stated coverage or yield to convert the result. Round only after accounting for the chosen allowance and packaging increments. For irregular spaces, divide the job into simpler sections and combine quantities with the same units.
Common question
Does the mass result tell me how many bags to buy?
Not by itself. Bagged products specify a mixed yield, which is usually a volume per bag. Divide the required volume by the product's stated yield and round up. The density-based mass is not a substitute for that product information.
Guide updated .