Concrete Volume Calculator
Calculate concrete volume required for slabs, footings, and columns.
Calculator
No signup required. Results are indicative—verify for your standards.
Net volume: 3.600 m³
Order quantity (with 10% wastage): 3.96 m³
Formula
Rectangular slab/footing: V = L × W × H (m³). Circular column: V = π × (D/2)² × H. Add 5–10% wastage allowance to the calculated volume.
Example calculation
Foundation slab 6 m × 4 m × 0.15 m: V = 6 × 4 × 0.15 = 3.6 m³. Add 10% wastage: 3.6 × 1.1 = 3.96 m³ → order 4 m³.
Engineering notes
Ready-mix concrete is typically ordered in 0.5 m³ increments. Standard mix proportions: M20 (1:1.5:3) for general structural use, M25 (1:1:2) for columns and beams, M30 for industrial floors. Always add 10% overage for pours to account for losses and uneven subgrade.
When to use this calculator
- Construction BOQ — calculate concrete quantities for foundation, slab, columns, and beams for a building
- RMC ordering — determine ready-mix concrete order quantity before pouring begins
- Cost estimation — compute concrete cost from volume × current RMC price per m³
- Industrial flooring — calculate concrete for plant room floors, equipment plinths, and paving
- Civil works tendering — prepare concrete volume take-off for civil subcontract quotation
Frequently asked questions
- What concrete grade should I use for different applications?
- M15 (15 MPa): mass concrete, blinding layers, non-structural fill. M20 (20 MPa): general slabs, footings, beams — minimum for reinforced concrete per IS 456. M25 (25 MPa): columns, retaining walls, industrial floors with moderate loads. M30 (30 MPa): heavy industrial floors, high-rise columns, water-retaining structures. M35+ (35 MPa+): bridges, precast structural elements, heavy foundations.
- How do I calculate the number of cement bags, sand, and aggregate needed?
- For M20 concrete (1:1.5:3 by volume), per 1 m³ of concrete approximately: cement 8–8.5 bags (50 kg each), sand 0.42 m³, aggregate (20 mm) 0.84 m³. For M25 (1:1:2): cement 10.5–11 bags, sand 0.35 m³, aggregate 0.70 m³. These are approximate — use the IS 10262 mix design procedure for critical structural elements to determine exact proportions based on aggregate properties.
- Why should I add a wastage factor to my concrete calculation?
- Wastage occurs from: uneven subgrade requiring more concrete to achieve design thickness, spillage during placing and vibration, over-pour at edges and formwork edges, and concrete that adheres to the mixer drum and chutes. Standard wastage allowances: 5% for simple pours with good formwork, 10% for general structural work, 15% for complex formwork with many penetrations. Under-ordering concrete is expensive (emergency additional pour) so always order with adequate buffer.