The formula for a piece of paper to wrap a parcel (dimensions L(Length)*B(Breadth)*H(Height)) is as follows:
(2L+2H+X)*(B+H+X), where X is the required overlap.
This is a more economic version of the widely used version, which was promoted in the national press as being the most economical solution, probably by wrapping paper companies. By using my formula, a saving of H-X per present can be made. Think of all the mince pies that could buy.