Compartments in all boxes are 5/16" deep. 8 compartment box measures 5" x 3.5" x 1/2" overall, compartments are 1" x 1 5/16". 12 compartment box measures 7" x 4" x 1/2" overall, compartments are 15/16" x 1 3/8". 18 compartment box measures 7" x 4" x 1/2" overall, compartments are 7/8" x 1 3/8".
