Box Strength


 Just like corrugated box styles, printed custom corrugated boxes can be manufactured using different strengths of corrugated paper. Some questions to ask yourself which strength of corrugated paper is best for your application would include but are not limited to the following:

  • How much will the contents weigh in my custom printed corrugated box?
  • What type of shipping environment will my custom printed corrugated box be traveling in?
  • Will any other corrugated boxes be placed on top of my custom printed corrugated box?
  • How fragile are my contents when placing them inside my custom printed corrugated box?

  • Types of Corrugated Paper
  • Single Wall (vs) Double Wall (vs) Triple wall Corrugated Boxes

 Basically, there are two types of corrugated paper – ECT and Mullen. There are three major differences between ECT and Mullen: Recycled content of the corrugated paper, how the paper is tested and/or measured for strength, and cost.

 ECT (Edge Crush Test) corrugated paper has a higher amount of recycled content than Mullen corrugated paper. The strength of ECT corrugated paper is directly related to the compression strength of both the liners and medium. In other words, how much weight can the corrugated box withstand before collapsing? ECT is typically measured in pounds per square inch for stacking strength. ECT corrugated paper is usually less expensive than Mullen corrugated paper.

 Mullen paper has a higher concentration of virgin material than ECT. Virgin material typically comes from new wood (IE: Logs, wood chips, etc.). Mullen will still have some recycled content; however, the amount of recycled content in Mullen paper will be much less than ECT paper. Mullen paper is rated by a “Bursting Strength” method. This method consists of how many pounds per square inch the test takes to “burst” through the linerboard. Mullen corrugated paper is generally more expensive than ECT corrugated paper.

 When comparing 32 ECT corrugated paper to 200 lb. Mullen corrugated paper, there are two very interesting details. Custom printed corrugated boxes made from 200lb corrugated paper have almost a 60% greater bursting strength than those same custom printed corrugated boxes made from 32 ECT corrugated paper. We also found that approximately 40lbs of product could go into a custom printed corrugated box made from 200lb. mullen corrugated paper where as only 30lbs. could go into a custom printed corrugated box made from 32 ECT.

 Should you have any questions or need additional assistance, then please do not hesitate to contact our experienced Customer Service Representatives. We are here to help.

 A single wall custom printed corrugated box consists of two outside liners and one medium also known as the flute (IE: Looks like a roller coaster in the middle of the two outside liners). This medium can have different heights (IE: A, B, C, E, F) and contributes to the custom printed corrugated box’s strength. The most common medium for single wall corrugated material is “C”.

 A double wall custom printed corrugated box consists of two outside liners, one inside liner and two inside mediums. The most common combination of mediums for double wall corrugated is “B/C”.

 A triple wall custom printed corrugated box consists of two outside liners, two inside liners, and 3 inside mediums. The most common combination of mediums for triple wall corrugated is “A/A/C”

 Listed below is a chart that better explains the difference between single wall and double wall corrugated material.

Corrugated Paper Options:



Single Wall Corrugated

ECT (Edge Crush Test) Capacity Pounds / Box Compressive Force(lbs per in.) Mullen (Burst Strength, lbs. per sq. in)
ECT 29 C 50 29 N/A
ECT 32 C* 65 32 200
ECT 40 C 80 40 250
ECT 44 C* 95 44 275
 * Most common custom printed corrugated boxes.


Double Wall Corrugated

ECT (Edge Crush Test) Capacity Pounds / Box Compressive Force(lbs per in.) Mullen (Burst Strength, lbs. per sq. in)
ECT 42 C 80 42 200
ECT 48 C* 100 48 275
ECT 51 C 120 51 350
ECT 61 C 140 61 400
ECT 71 C 160 71 450
 * Most common custom printed corrugated boxes.

 Should you have any questions or need additional assistance, then please do not hesitate to contact our experienced Customer Service Representatives. We are here to help.