A practical guide to corrugated board grades

Corrugated boxes are the workhorse of B2B packaging, but the terminology around them can be confusing. Board grade, flute, wall count and FEFCO style all describe different things, and choosing the wrong combination is an easy way to pay for protection you do not need, or worse, to under protect a product in transit. This guide explains the most common corrugated box grades and styles in plain language, so you can specify packaging that matches the job.

What corrugated board is made of

Corrugated board is a sandwich. One or more sheets of fluted paper are glued between flat liner papers. The flutes give the board its stiffness and cushioning; the liners give it strength and a printable surface. The number of flute sheets and the quality of the liners determine how strong, crush resistant and expensive the board will be.

Single wall corrugated board

Single wall board has one fluted sheet between two liners. It is the most common type of corrugated packaging and is suitable for light to medium weight products that do not face extreme stacking or handling stress. Typical uses include e-commerce cartons, shelf ready packaging and light industrial parts.

• Best for: products up to roughly 10 to 15 kg in non demanding supply chains.
• Common flute: C flute offers a good balance of print quality and cushioning; B flute is finer and better for die cut details.
• Cost: the lowest cost option for most everyday boxes.

Double wall corrugated board

Double wall board adds a second fluted sheet and a third liner, creating five layers in total. The extra material significantly improves stacking strength, puncture resistance and load stability. If your boxes will be palletised several layers deep or shipped through a parcel network, double wall is usually the safer choice.

• Best for: heavier products, export shipments, palletised goods and longer supply chains.
• Common flute: BC flute combines B flute on the outside for print and die cut quality with C flute inside for cushioning and compression.
• Cost: typically 30 to 50% more than single wall, but often pays for itself by reducing damage and returns.

Heavy duty and triple wall board

Heavy duty corrugated covers the strongest grades, including triple wall board with three fluted sheets and seven liners. It is used for bulk bins, export crates and industrial components where wooden boxes might once have been the default. These grades are specified by burst strength, edge crush test values and box compression test results rather than by wall count alone.

• Best for: heavy machinery parts, bulk agricultural products, export crates and high stack warehouse storage.
• Testing: ECT measures stacking strength; burst strength measures puncture resistance; BCT predicts the load a finished box can carry.
• Cost: significantly higher, but usually still cheaper and lighter than timber or solid plastic alternatives.

Matching a grade to a box style

Board grade decides how much load a box can take; the FEFCO style decides how it is made and closed. The two are specified together, so once you have settled on single wall, double wall or heavy duty, pick the style that suits the product. Our box style guide sets out every FEFCO family with diagrams, including 0201 slotted cases, 0300 telescope boxes, 0400 folders and the 0900 fitments series.

As a rule of thumb: light, regular products in short supply chains run well as a single wall 0201; heavier, fragile or export products usually need double wall and often a telescope box or a die-cut fitment.

How to choose the right grade and style

Start with the product, not the box. List the weight, dimensions, fragility and how many layers it will be stacked. Then match that to a board grade and a FEFCO style. A light, regular product in a short supply chain can use a single wall 0201. A heavy, fragile or export product usually needs double wall and possibly a more protective style like a telescope box or a die cut fitment.

If you are unsure, our free packaging review takes your product dimensions and current pack, then recommends the right grade and style. We manufacture in house in Letchworth and can sample a design before you commit to a production run.