Concrete Mix Ratio Calculator
Calculate precise cement, sand, and aggregate volumes for construction projects. Supports M10-M30 strength presets and material density adjustments.
About
Accurate material estimation prevents structural weakness and cost overruns in concrete slab construction. This tool computes the required mass and volume of cement, fine aggregate (sand), coarse aggregate (stone), and water based on total slab volume and standard mix design ratios. It accounts for the dry volume coefficient, typically 1.54, to compensate for material shrinkage and void filling when water is added.
Construction standards define specific grades (e.g., M20, M25) for different load-bearing requirements. M20 (1:1.5:3) is standard for reinforced concrete, while leaner mixes like M10 are used for leveling courses. Incorrect water-cement ratios can reduce compressive strength by over 40%. This calculator uses standard densities (e.g., Cement ≈ 1440 kg/m3) to convert volumetric ratios into purchasable weight quantities.
Formulas
The calculation starts by determining the wet volume of the slab and converting it to the dry volume required for mixing materials.
Total Dry Volume:
Material Volume Fraction:
Weight Calculation:
Weight = Volume × ρWhere ρ represents the density of the specific material (e.g., Sand ≈ 1600 kg/m3).
Reference Data
| Grade | Mix Ratio (C:S:A) | Compressive Strength (28 Days) | Typical Application |
|---|---|---|---|
| M5 | 1 : 5 : 10 | 5 MPa | PCC, Foundation Leveling |
| M7.5 | 1 : 4 : 8 | 7.5 MPa | Footings, Pathways |
| M10 | 1 : 3 : 6 | 10 MPa | Patio Slabs, Non-structural |
| M15 | 1 : 2 : 4 | 15 MPa | Pavement, Floors |
| M20 | 1 : 1.5 : 3 | 20 MPa | RCC Beams, Slabs, Columns |
| M25 | 1 : 1 : 2 | 25 MPa | Heavy Load Foundations |
| M30 | Design Mix | 30 MPa | High-Rise Structures |