Cement bags, sand and aggregate for M20 concrete
Quantities for nominal concrete mixes per IS 456 – dry volume method (wet volume × 1.54).
dry volume = wet volume × 1.54
cement (cum) = dry volume ÷ sum of ratio · 1 bag = 50 kg = 0.0347 cum
cement (cum) = dry volume ÷ sum of ratio · 1 bag = 50 kg = 0.0347 cum
Per 1 cum of concrete
| Grade (mix) | Cement | Sand | Aggregate 20 mm |
|---|---|---|---|
| M15 (1:2:4) | ≈ 6.3 bags | ≈ 15.5 cft (0.44 cum) | ≈ 31 cft (0.88 cum) |
| M20 (1:1.5:3) | ≈ 8.1 bags | ≈ 15 cft (0.42 cum) | ≈ 30 cft (0.84 cum) |
| M25 (1:1:2)* | ≈ 11 bags | ≈ 13.6 cft (0.385 cum) | ≈ 27 cft (0.77 cum) |
* IS 456 allows nominal mixes up to M20; M25 and above should be a design mix – the figure is only for orientation. Water–cement ratio about 0.45–0.50.
Example: M20 slab 20 × 30 ft, 5 inch thick
600 sq ft × 0.417 ft = 250 cft = 7.1 cum → cement ≈ 57 bags, sand ≈ 105 cft, aggregate ≈ 210 cft. Add 2–3% wastage.
Calculate for your own measurements with AI Onin – freeAI Onin is a free AI assistant for construction: material quantities, BOQ, cost estimates and site photo analysis. Values are approximate (India, 2026); always follow your structural drawings, IS codes and the manufacturer's data. Structural design must be checked by a licensed structural engineer.