Boxes are always measured from the inside and identified by their 3 dimensions as follows:

Length x Width x Depth

The length is the longest side; the width is the smaller of the two sides and the depth is top to bottom. 

To measure, open the box at the glue tab. 

• Lay on flat surface.   
• Measure each panel.  The glue tabs are generally standard as shown on the chart below.   
• When measuring depth, include only the body-  do not include the flaps in the 3 dimensional size! 

Scoring allowances take the thickness of the corrugated board
into consideration to give accurate inside dimensions. 
This is important to allow the appropriate amount of space for the product being packed.

SCORING ALLOWANCES