Corrugated Flute Types Explained: E, B, C and Double Wall
Corrugated board is made of a wavy paper layer — the flute — sandwiched between flat linerboards. The flute is what gives a box its strength, cushioning and thickness. If you are sourcing custom packaging for the first time, the alphabet soup of flute types is the first thing to understand.
The common flute types at a glance
| Flute | Approx. thickness | Strength profile | Typical use |
|---|---|---|---|
| E flute | ~1.5 mm | Thin, lightweight, smooth printing surface | Mailer boxes, retail packaging, light products |
| B flute | ~3 mm | Good crush resistance, all-round | E-commerce shipping, food and beverage carriers |
| C flute | ~4 mm | Best cushioning, taller structure | Shipping cartons, heavier goods |
| Double wall | 6–8 mm | Two flutes bonded, high stacking strength | Heavy, fragile or high-value items |
E flute: thin, tidy, print-friendly
E flute is the thinnest common flute. It takes sharp, detailed printing and looks neat on a shelf, which is why it is popular for retail boxes and mailer boxes for light products. It offers less cushioning, so keep it for items that do not need heavy protection.
B flute: the e-commerce all-rounder
B flute sits between E and C in thickness and offers a good balance of strength and weight. It resists crushing well and is a solid default for most shipping boxes, bottle carriers and beverage carriers.
C flute: cushioning for shipping cartons
C flute is taller than B flute, giving better shock absorption for goods in transit. It is a common choice for outer shipping cartons where stacking and rough handling are expected.
Double wall: when stacking and weight matter
Double wall board bonds two flutes together — for example B + C — creating a board that handles heavy loads and tall stacking. Use it for heavy equipment, large-format goods or anything that will sit at the bottom of a pallet.
How to choose
Start with three questions: How heavy is the product? Will boxes be stacked? Does the print need to be fine and detailed? Heavy and stacked → double wall; average shipping → B flute; light, printed, retail-facing → E flute. When in doubt, order a sample — it costs little and removes all guesswork.
See it, don't guess
Our Packaging Guide shows flute cross-sections and real usage examples. Send us your product details and we will recommend the right board.