Domoni, if I remember correctly, the shorter one is 2' x 12' x 28", and the longer one is 2' x 16' x 28". The depth could be 30". These are actually a little too deep. Landscape fabric goes from 2" below the rim all the way around the bottom. They rest on a U-shaped steel frame that keeps them up off the deck, so it can dry out below them. I would recommend using wider boards if you plan to build something like this, so there are fewer seams. Planters rot out first along seams, so minimizing seams reduces the surface area most subject to rotting.

Do these have casters underneath?