When to use this calculator
Estimate wet concrete volume for a rectangular slab. Net geometric volume only; add an allowance suitable for site conditions when ordering.
Explore the material quantities calculators for other questions in this topic. For a related calculation, use the Construction Contingency Calculator: Add a chosen contingency percentage to a project cost estimate.
PUTTING IT INTO PRACTICE
Concrete Volume: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Length (m) | 5 |
| Width (m) | 4 |
| Thickness (cm) | 10 |
| Result | 2 m³ |
- Check the input labels and enter the example values above.
- Apply the relationship: Volume (m³) = length × width × thickness/100.
- The result is 2 m³, rounded for display.
How to interpret your result
Net geometric volume only; add an allowance suitable for site conditions when ordering.
Calculate net geometric quantities first, then apply a project-specific allowance where appropriate. Coverage per bag or pack should come from the product label. Bulk density, trimming and compaction can substantially change order quantities.
Frequently asked questions
Does a geometric estimate include waste automatically?
Only when a waste or allowance input is provided. Otherwise add an appropriate allowance separately before ordering.
How do I use the concrete volume calculator?
Enter length (m), width (m), thickness (cm). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Volume (m³) = length × width × thickness/100.
What should I check before using the result?
Net geometric volume only; add an allowance suitable for site conditions when ordering.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
Calculators Map editorial process · Updated · Methods and limitations