Fractional sizing is the main concept behind the Gastronorm system. It allows different-sized GN containers to be interchangeable.
The standard Gastronorm size is 530 x 325mm (Full Gastronorm).
There is a total of 9 different sizes (GN pan size list / GN tray size list).
GN 1/1 – 530 x 325mm (Full GN)
GN 2/1 – 650 x 530mm (Double GN)
GN 2/4 – 530 x 162mm (Two-Quarter GN)
GN 2/3 – 354 x 325mm (Two-third GN)
GN 1/2 – 325 x 265mm (Half GN)
GN 1/3 – 325 x 176mm (One-third GN)
GN 1/4 – 265 x 162mm (Quarter GN)
GN 1/6 – 176 x 162mm (Sixth GN)
GN 1/9 – 108 x 176mm (Ninth GN)
The above are outer dimensions. There is a variety in depths to fit with different purposes.