Also known as: A Flute, B Flute, C Flute, E Flute, F Flute, Corrugation Profile
Flute type describes the size and frequency of the corrugations in fibreboard. Larger flutes (A, C) give greater cushioning and stacking strength; smaller flutes (E, F) give a thinner board with a smoother surface for printing and retail packaging.
Flutes are identified by letter, and the lettering is historical rather than sequential in size — A flute is large, B is smaller, C sits between them, and E and F are progressively finer.
Larger flutes are taller, so they hold the liners further apart. That increases the effective thickness of the board, improving both cushioning and vertical stacking strength. Smaller flutes produce a thinner, denser board with a flatter surface that prints well and folds crisply.
C flute is the general-purpose workhorse for shipping cartons, offering a good balance of stacking strength and printability. B flute is chosen where crush resistance and a flatter print surface matter. E flute is used for retail-ready boxes that need good print and a slim profile.
In multi-wall board, flutes are combined — BC and EB are common pairings — so the board gets the cushioning of the larger flute and the print surface of the smaller one.
Flute Types at a glance
| A flute | ≈ 4.7 mm — highest cushioning and stacking strength |
|---|---|
| B flute | ≈ 2.5 mm — good crush resistance, flat print surface |
| C flute | ≈ 3.6 mm — general-purpose shipping standard |
| E flute | ≈ 1.5 mm — thin, excellent print, retail boxes |
| F flute | ≈ 0.8 mm — very fine, small retail packaging |
| Combinations | BC, EB and similar for multi-wall board |
Common questions
Is there a corrugated flute chart with heights?
Yes. The corrugated flute chart in common use lists A flute at about 4.7 mm, C flute 3.6 mm, B flute 2.5 mm, E flute 1.5 mm and F flute 0.8 mm, with take-up factors of roughly 1.54, 1.43, 1.32, 1.27 and 1.25. Double-wall combinations such as BC and EB stack two flutes for heavier loads. The flute types guide has the full chart.
Which flute is best for heavy engineering goods?
For heavy items use a larger flute or multi-wall board — typically C or A flute in 5-ply, or BC combined board. These give the stacking strength and cushioning that heavy, dense loads need in a container or warehouse stack.
Need Custom Corrugated Boxes for your product?
We manufacture custom corrugated boxes at our Rajkot unit and dispatch across India. Send the product, size or weight and monthly quantity and we specify and quote within one working day.
Or read the full specification: Custom Corrugated Boxes