Measure the top (choose either the width or length) of the box and double it. (since the top and bottom are the same) For example the width might be 7", so double that figure is14"
Measure the depth of the box and double it. Example: 2" doubled is 4"
Add the results from step 1 and step 2 - That is 14" + 4" = 18" Add what you want for overlap. (say one inch). Now you have established a need for 19 inches of paper to completely wrap the box.
Step Two: Measure the paper
Roll out a good estimate on how much paper it should take.
Fold the paper across the Wrapmaster Ruler as shown in the picture. When the corner reaches 19 inches......
Step Three: Cut
Now just pull the paper across the edge and you have exactly how much paper you need! No waste! Of time or paper!