Box pleat (Kellerfalte)

The box pleat (German Kellerfalte) consists of two outward-facing knife pleats whose inside folds meet in the middle. From outside, an exact, box-like fold sits on the fabric; on the inside there is a deep fold cavity. Typically three times the visible pleat width is consumed: 3 cm of fabric yields 1 cm of visible pleat face.

The most important application on men's shirts is the centre-back box pleat below the yoke - it adds width and freedom of movement in the shoulder and back area without sacrificing the fitted silhouette at waist and cuff. A second action detail is the sleeve box pleat above the cuff. In business shirt manufacture (Eton, Charles Tyrwhitt, Seidensticker) the box pleat is a classic; slim-fit shirts often go without or use two smaller side pleats.

Other uses: box-pleated skirts (especially children's dresses and cheerleader uniforms), box-pleated kilts (Prince Charlie style), back pockets with box pleats (cargo pants, jacket inside pockets) and action box pleats on hiking and outdoor jackets. In construction the pleat is fixed with a twin-needle stitch or a saddle stitch at its upper end while remaining free below. Key variant: the inverted box pleat - here the 'box' faces inward so that two inward-folded knife pleats remain visible.