Estimate wet and dry concrete volume, cement bags, sand, aggregate, mixing water, waste allowance, and optional material cost for slabs, walls, footings, columns, and custom construction projects.
Select a shape, measurement system, and concrete mix.
Enter the project dimensions and concrete mix, then select “Calculate Materials.”
The calculator converts project dimensions into wet concrete volume and then applies the selected waste and dry-volume factors. It divides the resulting material volume according to the cement, sand, and aggregate ratio.
Loose cement, sand, and aggregate contain air voids. During mixing and compaction, the materials settle and occupy less space. A dry-volume factor is therefore applied when converting finished concrete volume into separate ingredient quantities.
Choose the unit system that matches your measurements and preferred cement bag size.
Calculate a slab, rectangular wall or footing, round column, or enter a known concrete volume.
Provide all required dimensions. The calculator automatically converts imperial measurements to metric internally.
Enter the cement, sand, and aggregate ratio specified for your work instead of relying on a generic ratio.
Use the calculated bags, bulk-material volumes, water, and optional cement cost as an ordering guide.
| Mix ratio | Cement | Sand | Aggregate | General estimating context |
|---|---|---|---|---|
| 1 : 1.5 : 3 | 1 part | 1.5 parts | 3 parts | Relatively rich nominal mix; use only where permitted by the project specification |
| 1 : 2 : 4 | 1 part | 2 parts | 4 parts | Common traditional estimating ratio for general concrete work |
| 1 : 3 : 6 | 1 part | 3 parts | 6 parts | Leaner nominal mix sometimes associated with non-structural or mass work |
| Engineered mix | Specified by weight, performance, and approved materials | Preferred for structural concrete and code-controlled projects | ||
Wet volume equals length × width × thickness. All dimensions must be converted to the same base unit.
Column volume equals π × radius² × height × number of columns.
Dry volume equals wet volume × (1 + waste percentage) × dry-volume factor.
Cement volume equals dry volume × cement ratio ÷ total mix parts. Cement weight is then estimated using a bulk density of approximately 1,440 kg/m³.
The number depends on concrete volume, waste, dry-volume factor, mix ratio, cement density, and bag size. The calculator combines these inputs and rounds the answer up to full bags.
No. Cement is the binding ingredient. Concrete is the finished mixture made from cement, fine aggregate such as sand, coarse aggregate, water, and sometimes admixtures.
A value near 1.54 is widely used for rough nominal-mix estimating, but actual batching, material properties, and mix design can require a different factor.
Do not assume a nominal ratio is suitable for structural work. Structural concrete should follow the approved mix design, drawings, specifications, engineering requirements, and local building codes.
Cement is normally purchased in complete bags. Rounding up helps avoid an insufficient quantity when the calculated requirement includes a partial bag.
No. It is based on the entered water-cement ratio and estimated cement weight. Moisture in aggregates, admixtures, workability, strength, durability, and site conditions can change the required water.