The standard pallet size is 48" X 40" with each deck board being 3 ½" wide 5/16" thick. There are other pallet sizes that are standard across different industries but the above described GMA pallet is the most common and makes up more than 30% of all pallets used in the USA.
They suggest standard pallet dimensions to be 48" x 40". Despite the group's name change in 2019, pallets of this size are still commonly referred to as GMA pallets. More than 30% of pallets produced in the U.S. each year are GMA pallets. The next most common pallet dimensions are 42” x 42” and 48” x 48” respectively.