Project Shape
Slab
Footing
Column
Circular
Dimensions
Cost Estimate (Optional)
0.00
cubic metres
0
With Waste
0
Bags Needed
0
Total Weight
-
Est. Cost
Material Breakdown (1:2:3 mix)
Cement
Sand
Gravel
| Material | Amount |
|---|
Tip: For a standard driveway or patio slab, 100-150mm (4-6 inches) depth is typical. Always order 10% more than calculated to account for spillage and uneven ground.
Common Concrete Mix Ratios
Mix ratios describe the proportion of cement : sand : aggregate (gravel) by volume.
Water-to-Cement Ratio
The water-to-cement ratio (w/c) is critical for concrete strength. A typical ratio is 0.45-0.55. Too much water makes concrete weak and prone to cracking. Too little makes it unworkable. A good rule of thumb: the concrete should hold its shape when squeezed but not crumble.
0.40
High Strength
0.50
General Purpose