Box strength: ECT vs burst test, in plain words
Look at the bottom of a shipping box and you will often find a round stamp called a box certificate. It tells you how strong the board is, using one of two ratings.
ECT: edge crush test
ECT measures how much force the board can take on its edge before it crushes, which is what happens to boxes at the bottom of a stack. It is the most common rating today. 32 ECT single wall suits most shipping boxes; 44 ECT is a stronger single wall; 48 ECT and up is usually double wall.
Burst (Mullen) test
The burst test measures how much pressure it takes to punch through the board, expressed in pounds (for example 200 lb test). It relates more to rough handling and punctures than to stacking. Some industries and shippers still ask for burst rated board.
Which one matters for you?
If your boxes get stacked on pallets or in a warehouse, ECT is the better guide. If your boxes are thrown around in parcel networks or carry sharp, heavy items, burst strength matters too. For most businesses, a sensible ECT rating with the right box size and a decent insert beats paying for heavier board.
Do not overbuild
Stronger board costs more and weighs more. We size the board to your contents, stacking height and storage time, with a safety margin, so you are not paying for strength you never use.
Ready for a price? Send us your box size and quantity and we will reply with options and a production date.
