Corrugated Board Flute Types Explained: A Complete Guide

Corrugated packaging is the backbone of modern shipping, storage, and product protection. One of the most important elements of corrugated board is the flute type—the wavy layer sandwiched between liner papers. Different flute profiles offer different levels of strength, thickness, cushioning, and printability.

Understanding flute types helps you choose the right packaging for your product, reduce costs, and improve performance.

What Is a Corrugated Flute?

A flute is the arch-shaped structure in corrugated cardboard that provides rigidity and shock absorption. The height and spacing of these flutes determine how strong or flexible the board is.
Flutes are measured by:
Thickness (mm)
Number of flutes per linear foot
Stacking and cushioning strength

Single-Wall Flute Types

E Flute (1.1–2 mm)
Thin and compact
Excellent print quality
Lightweight and cost-effective
Best used for:
Retail packaging, cosmetic boxes, electronics packaging, mailer boxes

B Flute (2.5–3 mm)

Good puncture resistance
Balanced strength and thickness
Performs well in stacking

Best used for:
Shipping cartons, food packaging, display boxes

C Flute (3.5–4 mm)

Most commonly used flute
Excellent cushioning and stacking strength

Best used for:
Shipping boxes, industrial packaging, fragile items

A Flute (4.5–5 mm)

Thickest single-wall flute
Maximum cushioning and impact resistance

Best used for:
Heavy-duty packaging, fragile products, glassware, machinery parts

Double-Wall BC Flute (6–7 mm)

Double-wall corrugated boards combine two flute layers for added strength.
BC Flute (6–7 mm)
Combination of B + C flutes
High compression strength
Excellent durability

Best used for:
Heavy products, export packaging, bulk shipping cartons

Double-Wall AB Flute (8–9 mm)

Combination of A + B flutes
Maximum strength and cushioning
Thick and rigid structure

Best used for:
Very heavy machinery, industrial goods, long-distance transport

Double-Wall BE Flute (3.6–5 mm)

Combination of B + E flutes
Strong with a smoother surface
Better print finish than thicker boards

Best used for:
Premium packaging, branded cartons, retail-ready shipping boxes

How to Choose the Right Flute Type

When selecting corrugated board, consider:

  • Product weight
  • Fragility
  • Shipping distance
  • Stacking requirements
  • Printing and branding needs

Choosing the right flute ensures product safety, cost efficiency, and professional presentation.