The formula
kg = length m × width m × thickness mm × density g/cm³ kg/m² = thickness mm × density
Keep length and width in metres and thickness in millimetres, and the units work out to kilograms with no conversion factor.
Typical densities (check your own compound)
- Natural rubber (NR) sheet: about 1.10 – 1.50
- SBR / general purpose: about 1.40 – 1.60
- Nitrile (NBR): about 1.30 – 1.50
- Neoprene (CR): about 1.40 – 1.60
- EPDM: about 1.20 – 1.50
- Silicone: about 1.15 – 1.30
The spread comes from filler: a cheap, heavily filled sheet is denser than a premium one. That is why a rate per kg and a rate per m² tell different stories for the same sheet.
Selling by kg vs by m²
If you sell by m², the thicker gauges carry more rubber per rupee - price each thickness from its own weight, not from one flat rate. If you sell by kg, remember the customer pays for filler too, and a density check on incoming compound protects you from paying for it twice.
Questions people also ask
How much does 1 m² of 3 mm rubber sheet weigh?
3 × density. At 1.5 g/cm³ that is 4.5 kg per m²; at 1.2 g/cm³ it is 3.6 kg.
How do I find the length of a rubber roll from its weight?
Length (m) = weight (kg) ÷ (width m × thickness mm × density). A 90 kg roll, 1.2 m wide, 5 mm thick, at 1.5: 10 m.
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.