Corrugated cardboards are differentiated through types of liner and the flute types. The kinds of flutes are categorised by its thickness as well as the number of flutes per linear foot. With the growing towards lighter packaging, companies use thinner flutes to make the packaging lighter. However, for more protection, thicker flutes can be used, which can make the packaging heavy.

With the increase in numbers of flutes per linear foot also increase protection as well as make the packaging more rigid while help in printing. With the growing concern about carbon footprint, microflute is attracting more attention of the brand owners and in the packaging industry. Therefore, F and N-type micro-flute are particularly benefiting from the growing demand.

The below image shows various types of flutes in the corrugated packaging.

A-flute was the first flute size, while other sizes are named for the order in which they were introduced afterwards. B-flute, the second, is smaller; C-flute is in between A and B. E and F flutes, introduced in the 1980s, are also known as microflutes because they are so small.

The microflute ratio is still low, which is partly because of the maturing market as well as reducing weight. According to FEFCO 2012 data, in Europe, B-flute predominates with 35% of the market. C-flute is only 14% of the European consumption, with 13% B/C double-wall and 11.5% E-flute and microflute.

As a rule of thumb, a carton made from the clay-coated recycled board (CRB) for light contents (up to 0.5 lb, 230 g) is made from the board that is 15–18 points thick (380–460 μm). Board for a 1-lb (450 g) load is 20–24 points (510–610 μm). Board for a 2 lb (900 g) of contents is 28–32 points (710–810 μm). However, for contents that weigh over 2 lb (900 g), a microflute corrugated board (E, F, or N flute) may be considered.