The Hidden Variable
Most people choose boxes by size and wall type (single vs. double). But the flute profile — the shape and size of the wavy middle layer — has a huge impact on performance. Understanding flutes lets you fine-tune your packaging for better protection, lower cost, or improved printability.
A-Flute: The Cushion King
At approximately 5mm thick with 33 flutes per foot, A-flute has the largest flutes and provides the best cushioning. Its thick profile absorbs impacts well, making it excellent for fragile items. However, its coarse surface is not ideal for high-quality printing.
A-flute is commonly used as the inner layer in double-wall constructions (AC or AB flute) where its cushioning complements a finer outer flute.
B-Flute: The Printer's Choice
At 3mm thick with 47 flutes per foot, B-flute has smaller, more densely packed flutes. This creates a smoother surface that is excellent for printing — making it the go-to choice for retail packaging, point-of-purchase displays, and any application where graphics quality matters.
B-flute provides good crush resistance but less cushioning than A or C flute. It is commonly used for canned goods, die-cut boxes, and retail packaging.
C-Flute: The All-Rounder
At 4mm thick with 39 flutes per foot, C-flute sits between A and B in size. It offers a good balance of cushioning, crush resistance, and printability. C-flute is the most widely used flute profile in the world — the default choice for shipping boxes.
If you are not sure what flute to specify, C-flute is almost always a safe bet. Most of the used boxes in our inventory are C-flute single wall.
E-Flute: The Micro Option
At just 1.5mm thick with 90 flutes per foot, E-flute is the thinnest standard profile. Its ultra-fine surface rivals paperboard for print quality while still providing more structure and cushioning than chipboard.
E-flute is used for mailer boxes, pizza boxes, cosmetics packaging, and other applications where thin profile and excellent printing are priorities.
BC-Flute: The Power Combo
BC double-wall combines B-flute (outer, for printing) with C-flute (inner, for cushioning). This is the standard construction for heavy-duty double-wall boxes — offering both strength and a printable exterior. If you see "double wall" on a box specification, it is usually BC-flute.