CFT, brass, cubic metre and ton: converting sand and aggregate quantities
1 brass = 100 cubic feet (CFT) = 2.832 cubic metres (m³). To get tons, multiply cubic metres by the material's bulk density in tons per cubic metre — measure it for your own material, because it changes with moisture and grading.
The units used in the sand and metal trade
Sand, M-sand and aggregate change hands in several units, often in the same business: a load is measured by its lorry box at the yard, billed in cubic metres on a tender, and weighed in tons at a weighbridge. Knowing how they relate avoids losses on every load.
- CFT (cubic feet): the volume of a lorry box, length × width × height in feet.
- Brass: a trade unit of 100 CFT.
- Cubic metre (m³): the metric volume unit; 1 m³ = 35.315 CFT.
- Ton (metric tonne): 1,000 kg, used when loads are weighed on a weighbridge.
Conversion formulas
- CFT = length (ft) × width (ft) × height (ft)
- Brass = CFT ÷ 100
- m³ = CFT ÷ 35.315, and CFT = m³ × 35.315
- 1 brass = 100 CFT = 2.832 m³
- Tons = m³ × bulk density (tons per m³), and m³ = tons ÷ bulk density
Worked example: one lorry box
A tipper box measures 14 ft long, 7 ft wide and is filled 2.5 ft high.
Volume: 14 × 7 × 2.5 = 245 CFT, which is 2.45 brass, or 245 ÷ 35.315 = 6.94 m³.
Weight: if your sand's bulk density is 1.6 tons per m³ (an example figure — use your own), the load weighs about 6.94 × 1.6 = 11.1 tons.
Quick conversion table (volume)
| CFT | Brass | Cubic metres (m³) |
|---|---|---|
| 100 | 1 | 2.83 |
| 200 | 2 | 5.66 |
| 300 | 3 | 8.50 |
| 500 | 5 | 14.16 |
| 1,000 | 10 | 28.32 |
Why a weight worked out from volume is only an estimate
Bulk density is not a fixed number. Wet sand is heavier than dry sand, fine and coarse grades pack differently, and a heaped or settled load holds more material than a loosely filled one.
To get your own figure, fill a lorry box you have measured, weigh it on a weighbridge, and divide the net tons by the box's volume in m³. Re-check when the material, source or season changes.
How RockPro handles it
In RockPro Yard, inward loads are entered by lorry box (length, width and height in feet) or by weighbridge weight. Each material has its own density, so CFT, brass, m³ and tons are converted automatically, and stock is valued at weighted-average cost per yard.
Frequently asked questions
How many CFT is one brass?
One brass is 100 cubic feet (CFT).
How many cubic metres are in one brass?
One brass is about 2.832 cubic metres, because 1 cubic metre is 35.315 CFT.
How do I convert CFT to tons?
Divide the CFT by 35.315 to get cubic metres, then multiply by the material's bulk density in tons per cubic metre. Measure the density of your own material on a weighbridge for an accurate figure.
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