When you look at a corrugated box, you will notice that it’s made of more than just flat cardboard. Inside the layers, there are wavy paper sheets called corrugated flutes. These flutes play a very important role, they give the box strength, protect the items inside, and help the box stay in shape during shipping or handling.

Each flute has a different thickness and strength level. The common types used in packaging are A, B, C, E, and F. Every type serves a different purpose depending on whether you need strong protection, good print quality, or a lightweight design. Understanding these flutes helps you choose the right packing box for your product.

Different Wall Structures of Corrugated Boxes

Corrugated boxes are not all made the same. Their strength also depends on how many layers they have. Here are the basic types:

Single Face: One corrugated medium is glued to a single flat sheet of linerboard. This construction offers cushioning but no backing on the opposite side.
Single Wall: Also called Double Face, this is the most common type where the corrugated medium is glued between two sheets of linerboard, providing good strength and protection.
Double Wall: Made with three sheets of linerboard and two corrugated mediums, this type offers extra durability and is often used for heavier or bulkier products. Moreover, it provides reliable protection during shipping and handling.
Triple Wall: It features four sheets of linerboard and three corrugated mediums, providing maximum strength for very heavy or industrial packaging needs.

Types of flutes in corrugated boxes

In corrugated packaging, the flutes A, B, C, E, and F flutes offer distinct characteristics that influence the box’s strength, thickness, and functionality.

A-flute

A-flute is the thickest and most substantial type of corrugated flute, featuring approximately 33 flutes per foot and a thickness of around 4.8–5 mm. Therefore, its wider, more pronounced arches provide excellent cushioning, making it ideal for protecting fragile or heavy products that require additional shock absorption.

Recommended For

B-flute

B-flute features around 47–50 flutes per foot and has a thickness of about 2.5–3.2 mm, making it thinner yet more rigid than A-flute. Its tighter, denser structure provides better puncture resistance and a smoother surface for printing. Many industries widely use it for transport packaging and retail applications.

Recommended For

  • Food and snack boxes
  • Cosmetic boxes
  • Pharma boxes

C-flute

Corrugated packaging commonly uses C-flute, which offers 39–43 flutes per foot and measures 3.5–4 mm in thickness. It provides excellent stacking strength and good crush resistance, making it suitable for both transport and display.

Recommended For

  • Shipping boxes
  • Fruit boxes
  • Retail boxes

E-Flute
E-flute is a thinner option featuring 90–96 flutes per foot and a thickness of about 1.2–2 mm. It offers a smooth surface perfect for high-resolution printing while still maintaining good crush strength. Its compactness makes it ideal for premium and space-efficient packaging.

Recommended For

F-flute
F-flute is the narrowest variety of corrugated flute, measuring approximately 0.8mm in thickness and containing roughly 125–130 flutes per foot. Additionally, it provides a highly smooth surface, making it perfect for intricate printing, die-cutting, and premium retail packaging. Furthermore, manufacturers often use F-flute for sturdy, compact packaging like tuck-end boxes, cosmetics, or point-of-purchase displays, where design and strength matter.

Recommended For

  • Premium cosmetic boxes
  • Tuck-end boxes
  • Point-of-purchase displays

Choosing the Right Flute for Your Packaging

You choose the appropriate flute based on the items you’re packaging and how you want to safeguard or showcase them.
Select A or C flute for robust or delicate products, since they provide extra durability and protection.
B and E flute provide the ideal combination of protection and display for retail packaging along with excellent print quality.
F-flute is perfect for intricate or high-end designs due to its sleek surface and delicate composition.

Roshan Packages Limited, along with its subsidiary Roshpack, continues to lead Pakistan’s packaging industry by providing innovative and high-quality solutions. Specializing in corrugated packaging, flexible packaging, and paper products, RPL and Roshpack offer comprehensive packaging services tailored to diverse industry needs. From durable corrugated boxes to customized packaging designs, the group is committed to enhancing product protection and supply chain efficiency. For expert advice on selecting the ideal corrugated structure for your packaging needs, contact Roshan Packages Limited at 042-35290734.