Abstract: The invention concerns a method for adjusting height of a crate or box made of flexible material, having a base and at least four side walls by folding. After the base has been placed in a generally horizontal, a horizontal crease is produced on each side wall, parallel to the base and at a height substantially equal to a top of a stack of objects. At least one oblique crease is produced in each corner of the crate, with one end located at the intersection between two horizontal creases and the other end located on an upper ridge of one side wall. The upper part of each side wall is folded towards the center of the crate, at an angle substantially equal to 90°. The various flaps are folded on one another, being separated by oblique creases, bringing the upper part of side walls in a substantially horizontal plane.