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Concrete Calculator

Work out concrete volume and the cement bags, sand, and aggregate you'll need for slabs, columns, footings, and steps.

Structural Dimensions
Mix Design & Materials Pricing
Material Unit Rates (₹)
Total Wet Volume
0 cu.m
Calculated Dry Volume
0 cu.m
Material Requirements Summary
Cement Bags 0 Bags
Fine Sand 0 T
Aggregates 0 T
Volumetric Mixture Proportions Dry split ratio
- - -
Cost Breakdown Estimate
Cement Bags: ₹0
Fine Sand: ₹0
Aggregates / Gravel: ₹0
Total Material Cost ₹0

Formula Reference

Formula

Concrete Volume Calculation Formula

Concrete volume formula computes cubic yards or cubic meters of wet ready-mix concrete required to pour rectangular slabs, footing...

Concrete Design

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How Concrete Volume and Materials Are Calculated

01

Wet Volume and Dry Volume Formula

Wet concrete volume is calculated per shape: slabs use Length x Width x Thickness, cylindrical columns use pi x radius squared x Height, and stepped stairs sum each rectangular step as Rise x Run x Width. After adding your waste buffer, the wet volume is multiplied by 1.54 to get the dry volume of loose cement, sand, and aggregate needed, since these materials shrink once mixed with water and compacted.

02

Mix Ratio Grades and Material Split

The dry volume is divided among cement, sand, and aggregate according to the selected mix grade ratio, such as M20 (1:1.5:3), M25 (1:1:2), or M15 (1:2:4). Each material volume is then converted to a practical quantity using standard densities: cement at 1440 kg per cubic meter in 50kg bags, sand at 1600 kg per cubic meter, and aggregate at 1800 kg per cubic meter.

03

Concrete Material Calculation Example

For a 3m x 3m slab at 0.10m thickness in M20 grade (1:1.5:3) with a 5% waste buffer, wet volume is 3 x 3 x 0.10 = 0.9 cu.m, which becomes 0.945 cu.m after the waste buffer and about 1.455 cu.m of dry volume after the 1.54 factor. The cement share of that dry volume works out to roughly 7.6 bags of 50kg cement, with the rest split into sand and aggregate.

04

When to Use Related Construction Tools

Once you know the concrete quantities for your slab, column, or steps, use the Construction Cost Calculator to estimate the full building budget, or the Tile Calculator when you move on to flooring the finished surface.

Good to know

Questions, answered

Quick answers about how this tool works.

Concrete volume is calculated by multiplying the structural dimensions. For slabs: Volume = Length * Width * Thickness. For circular columns: Volume = pi * radius^2 * Height.

Dry concrete materials (cement, sand, aggregates) shrink in volume when water is mixed. We multiply wet volume by a factor of 1.54 to find the raw dry volume of materials required.

For 1 cubic meter of M20 grade concrete (1:1.5:3 mix), you typically need about 8.2 bags (approx. 410 kg) of cement, along with 0.43 cubic meters of sand and 0.86 cubic meters of gravel.

Common grades include M20 (1:1.5:3) for slabs and beams, M25 (1:1:2) for columns and foundations, and M15 (1:2:4) for driveways and pathways.

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