Flute Types for Corrugated Boxes: B, C, E and F

Corrugated flutes are the wavy layers between the liners of a box. The flute you choose controls strength, cushioning, thickness, and print quality. Understanding B, C, E, and F flutes helps you pick the right box for your product. Here is a simple guide.

What is a flute?

The flute is the fluted (arched) medium sandwiched between flat liners. Larger flutes give more cushioning and stacking strength; smaller flutes give a thinner wall and a smoother print surface.

The main flute types

• C flute - the most common shipping flute; good strength and cushioning for standard cartons.
• B flute - thinner and firmer; good for die-cut boxes and a flatter print surface.
• E flute - thin with a smooth surface; ideal for retail and mailer boxes with high-quality print.
• F flute - very thin; premium small retail packaging with excellent print.

Choosing the right flute

Match flute to product weight and print needs. For strong shippers, C or double-wall; for printed mailers and retail boxes, E or F. See our box strength guide and mailer boxes guide.

Flutes and printing

Smaller flutes (E, F) print more crisply, which is why premium mailers use them. See the complete guide to custom printed boxes.

Frequently asked questions

Which flute is strongest?

Larger flutes like C, or double-wall combinations, give the most stacking strength and cushioning.

Which flute prints best?

E and F flutes have a smooth, thin surface that reproduces detailed print cleanly.

What flute do mailer boxes use?

Most printed mailer boxes use E flute for a balance of strength and print quality.

Pick the right box

Match flute to your product and print. Explore our custom corrugated boxes or the e-commerce boxes collection.