When it comes to shipping your products, you want to make sure that they are in a box that will not only hold their weight, but keep them safe during transit as well. Therefore, we thought it would be helpful if we provided a breakdown of the different corrugated boxes' weight classes.
The following is an overview of the different weight classes available for corrugated boxes when shipping, from the lightest options to the heaviest options.
For comparison purposes, we include both the Mullen burst test and edge crush test (ECT) figures. The burst test represents how much pressure can be applied before the wall of a box will rupture.
The edge crush test is an indicator of the top-to-bottom pressure needed before a box will be crushed. This is important if you will need to stack a number of boxes, especially in a warehouse environment, and is the most popular box standard.
What Factors Affect the Strength of Corrugated Boxes?
There are several factors that affect the overall strength of corrugated boxes. This includes:
- The paper type used in the liner board
- The fluting profile
- The thickness level of the base paper used in the liner board and fluting
The weight and type of paper combined play a crucial role in a corrugated box's ability to withstand the weight of other packages in transit. And corrugated boxes can be classified by their weight capacity, such as:
- Extreme lightweight
- Up to 65 pounds
- From 66 - 95 pounds
- From 86 - 100 pounds
- From 101 - 120 pounds
- From 121 - 280 pounds
- From 281 - 300 pounds
The corrugated packaging weight class that you need depends on the types of products you need to ship. Luckily, every weight class can be ordered in bulk or small volume, meaning we have you covered no matter what packaging solutions you may need.
Boxes for very basic items that you are not worried about getting crushed or taking stacking damage can be made from a single face board. Single face board includes one corrugated medium glued to one flat sheet of liner board, leaving the flutes visible on the inside and making the material easy to wrap around items.
If you are looking for a lightweight box between single face wrap and the standard single-wall 32 ECT box, a 26 ECT box can hold up to 35lbs.
Up to 65 Pounds
Once you start to have concerns about box strength or plan to ship your boxes to other businesses and consumers, 32 ECT comes into play. 32 ECT and 200# Mullen single wall boxes are the most standard corrugated boxes, with the ability to hold up to 65 lbs. This makes them a perfect B2B packaging solution.
Constructed from one corrugated medium which is glued between two sheets of liner board for added strength, they come in a variety of sizes to meet your packing and shipping needs.
From 66-95 Pounds
Here at 66-95 pounds, you are starting to get a little more serious about the weight of the product inside your box. You want a heavy-duty single wall box that is able to withstand the added weight while being handled, shipped, and stored. That means you’ll want to begin using a 275# Mullen or 44 ECT box.
From 86-100 Pounds
Although some single-wall corrugated boxes can capably hold up to 120 pounds, this range is generally considered the tipping point where you want to start thinking about double wall construction for added durability. Double-wall means that there are three sheets of liner board with two mediums in between, making two “walls” and greatly increasing the box strength.
Standard entry-level double wall boxes are 48 ECT or 275# Mullen.
From 101 to 120 Pounds
The next strongest box is 51 ECT or 350# Mullen double-wall, using a stronger liner board to hold up to 120 pounds.
From 121 to 280 Pounds
As the weight of your shipment increases, the chances are that its value will increase immensely as well. This is no time to scrimp on the packaging; instead, it is the time to call in the big guns – the triple wall.
Here, four sheets of liner board are constructed with three mediums in between, making 3 “walls” for maximum toughness. With their triple layer of protection, these corrugated boxes are rated 400# up to 1100# on the burst test and from 61 ECT up to 90 ECT.
From 281 to 300 Pounds
The largest and heaviest of corrugated boxes can withstand up to 1300# on the bursting test and carry an ECT of 155. Extra reinforcements may be used such as the carton being stapled shut rather than glued shut, or adding wood to the floor of the carton.
Aside from just the ability to hold many different weights, corrugated boxes are one of the best industrial packaging solutions thanks to their ability to protect your products, customize your brand, and keep your total costs low (not to mention the environmental perks).
The possibilities are endless, from the lightest to the heaviest of items there is a corrugated box that will cradle your product safely from start to finish!
For more information about custom packaging solutions, contact us at CS Packaging today or download our free Protective Packaging guide below:
Editor's note: This article was originally published in October 2020, and has recently been updated to reflect new and current information.