concrete
Concrete volume
Estimate ready-mix volumes for slabs or cylinders with waste.
Results are approximate. Verify with manufacturer specifications or consult a professional.
Project inputs
IMPERIAL
Enter a value in Your units.
Enter a value in ft.
Enter a value in ft.
Enter a value in ft.
Includes breakage, spillage, onsite adjustments
Material output
Updates instantly as you type.
Primary output
8.72yd³
8.72 yd³
≈ 8 yd³ primary output
Results are approximate. Verify with manufacturer specifications or consult a professional.
How it works
Frequently asked questions
Country defaults
United States · USD · imperial
Waste factor: 9.0%
Context & guidance
Results are approximate. Verify with manufacturer specifications or consult a professional.
About This Calculator
Accurately calculate the volume of concrete needed for slabs, foundations, columns, and other structural elements. This calculator accounts for standard waste factors (typically 5-10%) required by building codes to cover pumping losses, spillage, and finishing cuts. Supports both metric (m³) and imperial (yd³) units with automatic conversion.
Step-by-Step Instructions
Select Shape Type
Choose between 'Slab' for rectangular foundations and floors, or 'Cylinder' for columns and round footings. Slabs require length, width, and thickness. Cylinders need diameter and height.
Enter Dimensions
Input measurements in your preferred unit system. For slabs: length (typically 4-12m or 12-40ft), width (3-8m or 10-26ft), and thickness (0.1-0.3m or 4-12in). For cylinders: diameter (0.2-2m or 8in-6ft) and height (0.5-6m or 2-20ft).
Review Waste Factor
The calculator applies a country-specific waste factor (usually 5-10%) based on local building standards. This covers concrete lost during pumping, spillage, and cutting. You can adjust this if your project has specific requirements.
Calculate Volume
Click calculate to see the total concrete volume needed. The result shows both the base volume and the volume including waste. For slabs: Volume = Length × Width × Thickness. For cylinders: Volume = π × (Diameter/2)² × Height.
Order Ready-Mix
Use the calculated volume to order ready-mix concrete from your supplier. Standard truck loads are typically 6-10 m³ (8-13 yd³). Round up to the nearest truck load to avoid shortfalls.
Common Mistakes
Forgetting to account for waste factor
Always include the 5-10% waste factor. Running short means delays, extra delivery costs, and potential cold joints if you can't pour continuously.
Measuring dimensions incorrectly
Measure the actual formwork dimensions, not the finished floor area. Add 2-5cm (1-2in) extra if you're pouring over existing surfaces that need leveling.
Not considering reinforcement displacement
Rebar volume is negligible (typically <1% of total), so it's not deducted. However, for heavily reinforced sections (>3% steel), you might add 2-3% extra volume.
Ignoring unit system consistency
Ensure all dimensions use the same unit system. Mixing meters with feet will give incorrect results. The calculator handles conversion automatically if you switch units mid-calculation.
Pro Tips
Order 10-15% extra for small projects (<5 m³) to account for formwork irregularities and finishing needs.
For exposed aggregate or decorative finishes, add 5% extra volume to ensure you have enough material for the top layer.
Coordinate with your ready-mix supplier to schedule deliveries in 2-3 hour intervals to avoid cold joints.
Use the cylinder mode for round columns, but remember that most columns have square bases—use slab mode for those.
For sloped surfaces, calculate the average thickness: (min thickness + max thickness) / 2.
Keep a small reserve (1-2 m³) on-site for patching and touch-ups after formwork removal.