Question: how to find thickness with length width and mass?
Answer: Use the formula mass of foil ÷ (length of foil x width of foil x density of aluminum) to find the thickness of aluminum foil. The density of aluminum is 2.7 g/cm3. So if you have a piece of aluminum foil that is 15 cm long and 20 cm wide and weighs 1.8 g, the calculation is 1.8 ÷ (15 x 20 x 2.7).