The formula
kg/m² = Σ (thickness mm × density g/cm³) kg/m = kg/m² × width (m) roll kg = kg/m × length (m)
It works because 1 mm of material with density 1 g/cm³ weighs exactly 1 kg per square metre. So every layer contributes its thickness times its density, and the layers simply add up.
Worked example: 800 mm wide, 4-ply belt, 5 + 2 mm covers
- Top cover 5 mm + bottom cover 2 mm = 7 mm of rubber at 1.15 g/cm³ → 8.05 kg/m²
- 4 plies × 1.2 mm (fabric with its skim) = 4.8 mm at 1.2 g/cm³ → 5.76 kg/m²
- Belt: 8.05 + 5.76 = 13.81 kg/m²
- Per running metre: 13.81 × 0.8 = 11.05 kg/m
- A 100 m roll: about 1,105 kg
Where the number goes wrong in real factories
- Using one density for the whole belt. Cover compound, skim and fabric are different materials and must be weighed separately.
- Forgetting edge trim and skim. Both are real rubber you bought, even if the drawing does not show them.
- Weighing a sample once and using it for every size. Weight scales with width and thickness, so a new size needs a new calculation, not a guess.
Questions people also ask
What is the density of conveyor belt rubber?
Most cover compounds fall between 1.10 and 1.25 g/cm³; heat- and fire-resistant grades can run higher. Use your own compound’s measured density, not a textbook value.
How do I find the weight of a belt roll?
kg/m² × width in metres × length in metres. For 13.81 kg/m², 0.8 m wide and 100 m long: about 1,105 kg, before packing.
Can software do this for every size automatically?
Yes. In Aakar One the belt is drawn once, layer by layer, and weight, cost and a floor price come out for any width and length you are asked for.
Stop calculating this by hand
Aakar One does this arithmetic for every product and every size, then carries the result into the quote, the job card, stock and GST. Manufacturing ERP with CAD built in, made in India.