If your box is deemed by UPS to be heavier or larger than the weight and dimensions provided on the shipping label, you will be billed for the overage.
If you have a larger box than normal and it requires extra handling UPS will asses extra fee. These boxes are at least of 24 x 24 x 24 or total greater than 125 cubic inches.
To figure the cubic inches out please use the equation:
length (longest side of the package) plus girth [(2 x width) + (2 x height)].
If you ship anything without it being inside a box, UPS will bill a $50 fee.