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Guide to Corrugated Flutes

Corrugated cardboard is a versatile and widely used packaging material known for its strength, durability, and cost-effectiveness. The corrugated flute, the wavy layer between two flat paperboard sheets, is a key factor contributing to its strength. Understanding the different types of corrugated flutes, their dimensions, and their applications is crucial for selecting the right packaging solution for various products. This comprehensive guide will explore the major types of corrugated flutes, their dimensions in GSM (grams per square meter), and the corresponding sizes.

Single Face Corrugated Flute (Type F)

Single-face corrugated flute, or Type F flute, is the simplest formgroove. It consists of one flat sheet glued to a corrugated medium. This type is commonly used for wrapping and cushioning purposes. The thickness of the Type F flute can vary, but it is often around 2 mm.

Single Wall Corrugated Flutes

Single-wall corrugated flutes are among the most commonly used types in packaging. The major single-wall flute types include:

A-Flute (5mm)

A flute is the largest size, with fewer flutes per linear foot, resulting in better cushioning and stacking strength. It is commonly used for Small Shipping Boxes and retail displays. The thickness of A-flute is around 5 mm.

B-Flute (3mm)

B-Flute is smaller and more compact than A-Flute, providing a smoother surface for printing. It is often used for Custom Boxes requiring high-quality print surfaces, such as retail packaging. The thickness of the B-flute is approximately 3 mm.

C-Flute (4mm)

C-Flute is the most commonly used flute in corrugated packaging. It strikes a balance between cushioning and structural integrity. It is suitable for various applications, including Mailer Boxes and e-commerce packaging. The thickness of the C-flute is around 4 mm.

E-Flute (1.5mm)

E-Flute is a thin flute size that provides a smooth printing surface and is ideal for high-quality graphics. It is commonly used for packaging products like cosmetics and Pizza Slice Boxes. The thickness of the E-flute is approximately 1.5 mm.

Double Wall Corrugated Flutes

Double-wall corrugated flutes offer greater strength and protection. The major double-wall flute types include:


BC-Flute combines the B and C flutes, balancing strength and printability. It is commonly used for heavy-duty packaging applications. The thickness of the BC flute is around 7 mm.


EB-Flute combines the E and B flutes, providing a combination of strength and a smooth surface for high-quality printing. It is suitable for applications where both strength and aesthetics are important. The thickness of the EB flute is approximately 4.5 mm.

Triple Wall Corrugated Flutes

Triple Wall corrugated flutes are the thickest and strongest options, designed for heavy-duty packaging. The major triple-wall flute types include:

AAA-Flute (10mm)

AAA-Flute is the thickest flute size, providing exceptional strength and durability. It is used for heavy industrial applications, such as shipping large and heavy items. The thickness of the AAA flute is around 10 mm.

Corrugated Flute Dimensions in GSM

Understanding the dimensions of corrugated flutes is essential for choosing the right material for specific packaging needs. The following table provides an overview of the typical GSM and thickness in millimeters for various corrugated flute types:

Additional Considerations in Corrugated Flute Selection

Environmental Impact

In recent years, there has been a growing emphasis on sustainability and environmental considerations in packaging materials. Corrugated cardboard, being inherently recyclable and biodegradable, is considered eco-friendly. However, the environmental impact also depends on the type and thickness of the corrugated flute.

Thin Flutes and Sustainable Packaging

With its thin profile, the E-Flute contributes to lightweight packaging, reducing overall material consumption. This can be especially advantageous for companies aiming to minimize their carbon footprint and meet sustainability goals.

Recyclability of Corrugated Materials

All types of corrugated flutes are recyclable, contributing to a circular economy. A well-established recycling infrastructure exists for corrugated cardboard, making it an environmentally responsible choice.

Printing and Graphic Considerations

The surface smoothness of corrugated flutes plays a crucial role in the quality of printed graphics on packaging. Here’s a brief overview:

Smoothness for Better Graphics

E-Flute, known for its fine surface, is well-suited for high-quality printing. Businesses in the retail sector often prefer E-Flute for packaging, where visual appeal is a critical factor.

B-Flute and C-Flute Balance

B-Flute and C-Flute strike a balance between strength and printability. This makes them versatile choices for various applications where structural integrity and graphical presentation are important.

Application-Specific Recommendations

Understanding the specific needs of your product and the challenges it may encounter during transit is essential for effective packaging. Here are some application-specific recommendations:

Food Packaging

E-Flute is commonly used in the food industry, especially for items like pizza boxes and confectionery packaging, where a smooth surface for printing and lightweight yet sturdy construction are beneficial.

Electronics and Fragile Items

With its larger flute size, the A-Flute provides superior cushioning and stacking strength. This makes it an ideal choice for packaging fragile items, electronics, or products that require extra protection during transit.

E-commerce Packaging

C-Flute is widely used in e-commerce packaging due to its balance of strength and printability. It can withstand the rigors of shipping while offering a good surface for branding and product information.

Corrugated Flute Innovations

Technology and material science advancements have led to innovations in corrugated flutes to meet specific industry demands. Some notable innovations include:

Water-Resistant Flutes

Corrugated flutes with water-resistant coatings are gaining popularity in applications where exposure to moisture is a concern. This can be crucial for Custom Product Packaging that may be stored or transported in humid conditions.

Flutes with Greater Strength

Developments in corrugated flute composition have led to flutes with greater strength characteristics. These innovations are particularly beneficial for heavy-duty packaging, ensuring the protection of goods during transit.

Regulations and Compliance

Understanding packaging regulations and compliance standards is vital to ensure that your packaging meets industry and regional requirements. Corrugated materials generally comply with international standards, but staying informed about any regulation updates or changes is essential.


While selecting the right corrugated flute is crucial for effective packaging, considering environmental impact, print quality, application-specific requirements, and staying updated on innovations and regulations are equally important. By taking a holistic approach to corrugated flute selection, businesses can optimize their packaging processes, reduce environmental impact, and meet the industry’s evolving demands.

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