Corrugated cardboard is a packaging material made of layers of kraft paper with one or more corrugated sheets (channels) sandwiched between them. Its structure provides resistance to crushing and stacking, making it the most widely used material in the world for manufacturing shipping, moving, and transport boxes.
What is corrugated cardboard?
Corrugated cardboard (also called fluted or corrugated board) is made up of a combination of two or more sheets of paper called "liners" glued to an inner corrugated cardboard sheet. These paper layers are assembled in such a way that they form a series of interconnected arches , capable of supporting heavy loads.
The air circulating within the corrugations (channels) also acts as thermal insulation , providing protection against temperature fluctuations. This makes corrugated cardboard a renewable and sustainable natural resource, ideal for modern packaging .
Detail: Corrugated cardboard roll (single layer of corrugated paper)
Details: Corrugated cardboard with 3 layers (two layers of kraft paper + one central corrugated layer)
Types of corrugated cardboard channel
The "flute" is the internal corrugation that gives cardboard strength. Each type of flute has a specific thickness and function:
| Channel type | Approx. thickness | Characteristics | Main use |
|---|---|---|---|
| Channel A | ~5 mm | Maximum cushioning | Moving boxes , fragile items |
| Channel B | ~3 mm | Good durability, compact | Standard shipping boxes, feed |
| Channel C | ~4 mm | Multipurpose, the most used | General packaging, ecommerce |
| E channel (microchannel) | ~1.5 mm | Fine, good impression | Presentation packaging, displays |
| Dual channel (BC, EB) | ~7 mm | Maximum resistance | Heavy shipments, international removals |
How to measure the strength of cardboard?
In the packaging industry, two main tests are used to measure the quality of corrugated cardboard:
- ECT (Edge Crush Test): Measures how much pressure the cardboard can withstand when compressed along its edge. The higher the ECT, the more boxes you can stack without them collapsing. This is the most relevant data for boxes that will be stacked on pallets.
- BCT (Box Compression Test): Measures how much weight the entire box can withstand (not just the contents). It depends on the box size and the type of flute. It's the most practical test to determine if your box will withstand stacking in a warehouse.
What type of corrugated cardboard do you need?
The choice depends on the weight of your product and the shipping conditions:
- Products up to 5 kg: Channel B or E → postal shipping boxes, ecommerce
- Products weighing 5 to 15 kg: Channel C or A → standard moving boxes, electronics
- Products weighing 15 to 30 kg: A-channel or double channel → reinforced boxes, moving
- Products >30 kg or international shipments: Double channel required
At TeleCajas you can find single-wall and double-wall corrugated cardboard boxes for all types of shipments. If you need reinforced moving boxes, check out our collection of moving boxes .
Differences between corrugated cardboard and cardboard
Not all cardboard is the same. Corrugated cardboard has internal fluting that gives it strength; paperboard is a flat sheet without fluting, much thinner, used for presentation packaging (cereal boxes, perfumes, medicines). If you want to know the differences in detail, see our article on paperboard vs. corrugated cardboard .
Need to know which adhesive tape to use to seal your corrugated cardboard boxes? Read our comparison guide.
