Definitions & Formulae

Definitions and Formulae

Aperture (w)



Wire Diameter (d)



Mesh Count (n)




Pitch (p)









Open Area %




Space between adjacent parallel wires, in mm.

(25.4 / n) – d


Diameter of wire before weaving, in mm.



Number of apertures per lineal inch measured from the centre of one wire to a point 1 inch (25.4 mm) distant.

25.4 / (w + d)


Distance between the centres of two adjacent wires in mm.

w + d or 25.4 / n


Wires running lengthwise in the cloth as woven.



Wires running crosswise in the cloth as woven.



The fractional open surface area of the wirecloth in the flow direction

(w²) / (w + d)² * 100 (applicable for square meshes only).


The fractional void volume of the mesh.


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