Wooden Soap Molds

Me know the inside dimensions are 5 "long 3 1 / 2 inches wide and 2 3 / 4" deep, what size would I need to cut the planks? Let me use 1x4 boards to make this box.

a1x4is a true 3/4x3 1/2inch you need two 6 1 / 2 x 2 3 / 4 and two 3 1 / 2 x 2 3 / 4 in the mold on the services available to fill the mold plate caught up Turn hard plastic mold line rap keeps soap paste

It depends on the thickness of the boards are cut to create this soap mold. I do not think I'd trust someone with a saw that does not know math. The dimensions are length, width, depth and thickness. Do the math.