At first glance, a cardboard box looks like one of the most straightforward items around. However, upon further investigation, cardboard boxes are more complicated than you’d think, thanks to various design and structural components, plus their usefulness in promoting your brand

One of these components is known as a “flute.” Not a musical instrument, this component is vital to the structure and composition of corrugated packaging. 

What Are Corrugated Flutes?

Corrugated flutes refer to the layers of corrugated material that are arranged in wave-like patterns between layers of the liner. So while you may not be able to see corrugated flutes at first glance, they play an important role in corrugated packaging to make it one of the best shipping methods available. 

What Is the Purpose of Corrugated Flutes?

Corrugated flutes are designed to provide corrugated packaging with extra layers of insulation and protection. They also help make the packaging crush-proof and puncture-proof. Finally, corrugated flutes help provide structure to corrugated boxes, so they support heavier items without folding or breaking. 

What Are the 5 Different Types of Corrugated Flutes?

The five types of corrugated flutes are: 

  • A flutes
  • B flutes
  • C flutes
  • E flutes
  • F flutes

These flutes range in size from 5 millimeters thick to 0.8 millimeters thick. And while it may seem that the flutes are named in order according to size, they are actually named according to when they were invented — with A being the first flute invented and F being the last flute invented. 

A Flute

A flute is the thickest corrugated flute available, measuring at about 5 millimeters or ¼ inch in thickness. This means that there are about 36 flutes within a single linear foot of packaging. 

An A flute is ideal for fragile items that need extra protection, thanks to extra-thick fluting. This flute is also ideal for heavier items that require a strong packaging structure. 

B Flute

The B flute falls in the mid-range, measuring at about 3.2 millimeters or ⅛ inch in thickness. This means that there are about 49 flutes within a single linear foot of packaging. 

The B flute is ideal for inner packaging components as it is crush- and puncture-resistant. This flute is also ideal for printing words, graphics, and logos directly onto the corrugated cardboard. 

C Flute

The C is the second-thickest corrugated flute available, measuring about 3.2 millimeters or 11/64 inches in thickness. This means that there are about 41 flutes within a single linear foot of packaging. 

A C flute is ideal for shipping boxes as it is also crust-resistant and is not easily compressible. Like B flute, it also provides a good printing surface for branded and marketing materials. 

E Flute

The E flute is the second-thinnest corrugated flute, measuring about 1.6 millimeters or 1/16 inch in thickness. This means that there are about 90 flutes within a single linear foot of packaging. 

An E flute is ideal for reducing storage space and costs since it is quite thin. This flute is also commonly used for the packaging of consumer goods. 

F Flute

The F flute is the thinnest corrugated flute available, measuring at about 0.8 millimeters or 1/32 inch in thickness. This means that there are about 128 flutes within a single linear foot of packaging. 

The F flute is ideal for stiff packaging needs for some types of consumer goods. 

Other Factors to Consider With Corrugated Packaging

In addition to corrugated flutes, there are other factors you need to consider when choosing your corrugated packaging, specifically board type, box style, and printing type. Here’s what you need to know about each of these factors so that you can choose the best-corrugated packaging for your specific products and overall brand: 

Board Type

While all corrugated packaging materials are made up of a combination of both flutes and liners, the exact combination varies. There are four different board types with different combinations of flutes and liners to consider: 

  • Single-face: A single-face board only has two layers with one layer of fluting and one layer of liner. This means that it’s not as durable as other board types since it’s missing a second liner. However, this type of board is ideal for inner packaging components that add extra cushioning to contents. 
  • Single-wall: A single-wall board is the most common board type used with one layer of fluting surrounded by two liners — one on each side. This type of board is commonly used in shipping cartons as it provides adequate insulation and contents protection. 
  • Double-wall: A double-wall board has five layers — three layers of liner surrounding two layers of fluting. Essentially, this double-wall is like two boxes in one. This means that it’s extremely durable and is ideal for use with heavy industrial items. 
  • Triple-wall: A triple-wall board has seven layers — four layers of liner surrounding three layers of fluting. Similar to the double-wall, this board is like three boxes in one. As the most durable board type available, triple wall packaging is often used for shipping crates and chemical containers. 

Box Style

While you may think that corrugated cardboard only comes in the form of your basic square box, this actually isn’t the case. Instead, corrugated flutes and liners can be incorporated into countless different box styles. 

Here are some different box styles to consider for your products and brand: 

  • Mailer box: A mailer box is designed to be efficient, protective, and stylish thanks to smart features like dust flaps that effectively seal and protect the contents of the package. Ecommerce and subscription businesses frequently use mailer boxes for their products. 
  • One-piece folder box: A one-piece folder box is designed to be simple, sleek, and easy to assemble. This box consists of a single piece of corrugated cardboard that can be quickly and easily assembled to ship out items like books or artwork. 
  • Shipping box: A shipping box is designed to be classic and traditional yet protective, thanks to a single wall design with B fluting. This box can be used to ship just about anything. 

Printing Type

Corrugated packaging doesn’t have to be the plain and boring brown cardboard that you see everywhere. In fact, you can print directly onto the cardboard. This is the perfect branding opportunity as it allows you to show off your logo and products. When it comes to printing onto corrugated material, there are a few different options, including flexographic, lithographic, and digital. 

Lithographic printing is ideal for bulk printing jobs as customized plates need to be designed in order to guide the printing process. Flexographic printing is the most commonly-used printing type as it is quick, easy, and cost-efficient. Finally, digital printing is ideal for small-scale printing jobs since there’s no need for customized plates. 

Final Thoughts on Corrugated Flutes

Now that you have a better understanding of corrugated flutes, you’re able to make informed packaging decisions. However, if you have any additional questions about packaging, feel free to reach out to the experts at Box Genie.



  1. Corrugated Material - An Overview | ScienceDirect
  2. Digital Printing: A Packaging Revolution | Packaging Strategies
  3. ​​Importance of Product Packaging in Marketing | Small Business Chron

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