Standard Imperial 'Inch' picture frame sizesInchesCentimetres (cm)Milimmetres (mm)12 x 12 inch30.48 x 30.48 cm304.8 x 304.8 mm12 x 16 inch30.48 x 40.64 cm304.8 x 406.4 mm14 x 14 inch35.56 x 35.56 cm355.6 x 355.6 mm16 x 16 inch40.64 x 40.64 cm406.4 x 406.4 mm