The three units you'll meet
- Cubic metre (m³) — the SI unit, used for concrete volume and in mix design.
- Cubic feet (cft) — common for cement (one 50 kg bag is about 1.226 cft) and for quoting sand and aggregate.
- Brass — an Indian unit equal to 100 cubic feet, used for ordering sand and aggregate by the truckload.
The conversions
| From | To | Multiply by |
|---|---|---|
| 1 m³ | cft | 35.3147 |
| 1 brass | cft | 100 |
| 1 brass | m³ | 2.83168 |
Why the units matter on site
Construction in India straddles three measurement systems at once, and mixing them up costs real money. Engineering drawings and concrete volumes are in cubic metres; cement is counted in 50 kg bags; and sand and aggregate are most often bought by the cubic foot or the brass. A supplier who quotes ₹X per brass and a drawing that specifies cubic metres are describing the same material in different languages, and ordering against the wrong one can leave you short or with costly surplus.
Worked conversion example
Suppose a calculation gives 3 m³ of sand. In cubic feet that is 3 × 35.3147 = 105.9 cft, and in brass that is 105.9 ÷ 100 = 1.06 brass. So you would order about one brass of sand. If your supplier instead quotes per tractor-load, ask how many cubic feet a load holds — it is commonly around 100 cft (one brass), but it varies, so confirm rather than assume.
A note on weight vs volume
Brass, cft and m³ are all volume units, but materials are sometimes sold by weight (tonnes), especially aggregate. To convert, multiply the volume by the material's bulk density — about 1550 kg/m³ for sand and 1500 kg/m³ for aggregate. One brass of sand therefore weighs roughly 4.4 tonnes. Because damp sand bulks up and weighs more per volume, weight-based selling can differ from volume-based, which is another reason to be clear which basis your supplier uses.