The Edge Crush Test and You: Preventing Disaster when Shipping Your Boxes and Packages

Posted by Marty Boyer on

 Your guide to Edge Crush Tests

  • Edge Crush Tests (ECT) help determine the strength of corrugated material
  • ECTs are often used alongside Mullen tests to determine durability
  • 32 ECT is the current standard for boxes
  • ECTs and Mullen tests can help you determine what boxes are right for your business
  • 3D Corrugated specializes in ECT knowledge to help businesses throughout Greater Cincinnati and Northern Kentucky meet their shipping goals and needs


Unless you work in the box-making industry or are really up to speed on your manufacturing acronyms, you likely have no idea what the aforementioned letters mean. But, as many businesses in the Greater Cincinnati/Northern Kentucky region that routinely use and rely on corrugated packaging may know, they are very important. That’s because ECT stands for “Edge Crush Test,” a measure that – depending on its results – could mean the difference between very happy customers or lot of requests for refunds, damaged items, and possible lost business.

Learn how an ECT works and how 3D Corrugated uses it to find the proper boxes and packaging for customers like you on a daily basis.



In its simplest terms, an ECT tells you exactly how much weight can be stacked on top of a corrugated sheet (or box) before the it is crushed. It’s measured by taking a corrugated sheet (a.k.a. the material that makes up a box) and applying weight to the edge of the sheet until it crushes. You can also think of it as pressing down a section of corrugated board on its edge (on its flutes) perpendicularly between two rigid plates until it collapses. This is the laboratory method used by manufacturers of corrugated cardboard to figure out the exact resistance of the material, which is useful since the corners and edges of boxes are mostly responsible for bearing loads.

In terms of numbers, 32 ECT is currently the industry standard among regular slotted cartons/containers (RSC). Regular slotted cartons consist of two outer flaps that are half the container’s width that meet in the middle when closed and are the type of corrugated boxes on the market today, which is why you’ll often hear them mentioned together with ECT. But to understand the significance of that, it helps to also understand what a Mullen test (also called a “burst”) test is. Whereas an ECT measures the box’s top-to-bottom strength, think of the Mullen test like dropping a weight on the side of the corrugated material until it bursts through.

With corrugated boxes typically constructed of single, double or triple wall boards, knowing the ECT and Mullen Score of a box can come in handy for the higher the rating, the more weight it can stand or contain. The ECT and Mullen crush test ratings for a single wall board box are as follows: 

Max. Suggested Load Per Box

ECT Min. Rating Needed

Mullen Rating (in pounds per square inch)

35 pounds

26 ECT

150 pounds

50 pounds

29 ECT

175 pounds

65 pounds

32 ECT

200 pounds

95 pounds

44 ECT

275 pounds

120 pounds

55 ECT

350 pounds

Currently, 32 ECT is the most commonly used corrugated material. But with treatments available to make boxes more water resistant and aforementioned double and triple wall boards, there are plenty of ways to ensure your boxes are safe for shipping.



Choosing the right corrugated material for your box typically depends on three things: (1) How heavy are the contents of your box? (2) What is the max weight that could stacked on top of your box when bundling or warehousing (if it is not being used to ship product to another destination) and (3) What happens to it during shipping and handling, a.k.a. is your box sturdy enough to handle transport?

There are good reasons an edge crush test is performed. First, it allows for quality control, which is important when you may be shipping valuable items across long distances. If you saw any pictures from United States Postal Service (USPS) locations this past holiday season, you already know that services like USPS, UPS and FedEx are working with hundreds if not thousands of parcels on a daily basis.

Second, an ECT can help a manufacturer determine the exact amount of corrugated cardboard needed to optimize the package without using more material than necessary, resulting in a higher cost to the consumer. Combined with void fill (learn more about its importance by clicking here), using a strong enough level of corrugated will result in a properly packed shipment and prevent problems.

Protecting merchandise is key for businesses, not just for the sake of their merchandise, but also their reputations. Shipping – both in terms of speed and security – is a key factor in feedback on sites like eBay, Amazon and others. Is there a worse feeling than getting something in the mail you’ve been anticipating only to discover it’s damaged?

At 3D Corrugated, our expertise in boxes and corrugated materials ensures that everyone we serve, be they in the Greater Cincinnati/Northern Kentucky region or beyond, gets the same quality service and products they need to support their business. So, whether you need boxes today or for us to warehouse them until you do, you can rest assured that, we are here to serve with tested materials at the ready.

Have questions about ECT? Shoot us an email at or give us a call at (513) 241-8126.



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