How much weight can my box hold?
If I put something really heavy in it will it break?
Should I use extra tape?
​These questions come up all the time in the packaging industry.It would not be fun to put a whole package together and wrap it and tape it, only to find out later that it broke during shipping.
Thankfully there are guides to help clarify what weight increments your shipping box can handle.

There are two guides to figure out the strength of your box.

  1. The Mullen test/bursting test
  2. The Edge Crush Test (ECT)

Essential they both tell you the same thing “ how much weight can your box hold before breaking”,
But they get there a little differently. You can find them both on the bottom of your box inside the box certificate.
The bursting test – is just how it sounds, how much pressure can be applied to a square inch of your box before puncturing.
The edge crush test – tests how much force can be applied to the box as a whole before breaking. It works by applying pressure to one of the corrugated sides and seeing how much pressure it can withstand when vertical before collapsing.


There are about 15 different test outcomes per box but you rarely see all them.
An average user will encounter 3 basic tiers. For standard , Heavy duty and Heavy Duty double wall. Here is map that you can use to see the loading limit per each grade of box and test. Notice the numbers for a Mullen test will be in the hundred and 200 range while ect usually stays under 100.This was a basic guide to help you start off, so get packing!  ​