Concrete / Cement Calculator

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Calculate cement bags, sand, and aggregate (coarse stone) required for slab, column, or footing construction.

Structure Details

m

m

m

Typical slab: 0.1–0.15m

Concrete Grade (Mix Ratio)

M10 – 1:3:6 (Plain concrete, PCC)

M15 – 1:2:4 (General construction)

M20 – 1:1.5:3 (RCC beams, columns)

M25 – 1:1:2 (High strength RCC)

Volume of Concrete Required

3.000

Dry volume (with 54% bulkage factor): 4.620

Materials Required (M20)

MaterialQuantityUnitNotes
Cement24.2Bags (50kg)1210 kg total
Sand (Fine)1.260≈ 2016 kg
Aggregate (Coarse)2.520≈ 3780 kg
Water605LitresW/C ratio: 0.5

About Concrete Calculation

Choosing the right grade

M10 – Plain Concrete (PCC): blinding layer, mass concrete, non-structural

M15 – Mild structural work, simple foundations

M20 – Most common for RCC: slabs, beams, columns, most residential construction

M25 – High-strength: bridge components, heavy-load structures

Why 1.54 dry volume factor?

When cement, sand, and aggregate are mixed and water is added, voids are filled and the overall volume reduces. To get the required wet concrete volume, you need 54% more dry materials. This factor (1.54) accounts for this compaction and void-filling.

Thumb rules for quick estimation

1 m³ of M20 concrete needs ~8 bags of cement (50kg each)

Standard 100mm slab for 1000 sq ft = 9.3 m³ concrete = ~75 bags cement

Order 5–10% extra materials to account for wastage and spillage

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