Cement, sand and aggregate calculator
Estimate cement bags, sand and aggregate for a nominal-mix concrete slab, footing or beam from its size and mix grade.
How much cement for a 10 × 10 ft slab?
A 10 ft × 10 ft slab that is 4 inches thick holds 0.944 m³ of concrete. In M20 (1 : 1.5 : 3) with 5% wastage it needs about 8 bags of cement, 0.42 m³ of sand (about 15 cft) and 0.83 m³ of coarse aggregate (about 29 cft). Enter your own sizes above to get your numbers.
| Material | Quantity | In common trade units |
|---|---|---|
| Cement | 7.99 bags (400 kg) | buy 8 bags of 50 kg |
| Sand | 0.42 m³ | 14.7 cft · 0.15 brass |
| Coarse aggregate | 0.83 m³ | 29.4 cft · 0.29 brass |
How is the quantity worked out?
The calculator multiplies length, width and depth to get the volume of wet concrete, then multiplies by 1.54 to allow for the dry materials that shrink into that volume. It splits the dry volume by the cement : sand : aggregate proportions of the chosen mix, and converts cement to 50 kg bags using a cement density of 1,440 kg per cubic metre. Cement is shown rounded up to whole bags, because it is sold that way.
What does it assume?
- Common site volume ratios: M5 (1:5:10), M7.5 (1:4:8), M10 (1:3:6), M15 (1:2:4) and M20 (1:1.5:3). IS 456:2000 itself gives nominal mixes by mass of aggregate per 50 kg of cement, so these ratios are estimating conventions.
- Grades richer than M20 are not offered, because they should be design mixes specified by your structural engineer. Reinforced concrete must not be weaker than M20 (IS 456:2000, Table 5).
- A dry-volume factor of 1.54, a 50 kg bag and a cement density of 1,440 kg/m³. One brass is 100 cubic feet.
- Water, admixtures and the moisture bulking of sand are not included. Order extra for your site's wastage.
Sources
- IS 456:2000, Plain and Reinforced Concrete: Code of Practice (cl. 9.3 and Table 9 for nominal mix concrete, Table 5 for minimum grades).
- The volume ratios, the 1.54 dry-volume factor and the 1,440 kg/m³ cement density are common estimating conventions, not clauses of the Standard.
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General information only. It is not a structural design or professional advice. Ask a licensed structural engineer or architect to check your plans and site.