4' x 8' x 18mm thick plywood weight?

Answer 1

It depends on the density of the plywood. This site shows some plywood densities in kg/m^3. Let's say your plywood is 500 kg/m^3 (which is at the low end of the plywood densities isted on that page). Converting the dimensions of the plywood to meters gives the following:

height: 4 ft = 4 ft * (12 in/ft) * (2.54 cm/in) * (1m/100cm) = 1.22 m

width: 8 ft = 8 ft * (12 in/ft) * (2.54 cm/in) * (1m/100cm) = 2.44 m

thickness: 18 mm * (1m/1000mm) = .018 m

The volume of the plywood is height * weight * thickness = 1.22 * 2.44 * .018 = .0535 m^3.

Weight is density * volume. So, at 500 kg/m^3, the plywood would weigh: 500*.0535 = 26.8 kg. 1 kg is approximately 2.2 pounds, so 26.8 kg is 26.8 kg * (2.2 lb/kg) = 58.9 pounds. If, however for example, your plywood is 700 kg/m^3, it would weigh 40% more, or 82.5 pounds.