§ Metric conversion table. Inches Millimeters (mm) 1/4 equals 6.4 3/8 equals 9.5 1/2 equals 12.7 9/16 equals 14.3 5/8 equals 15.9 3/4 equals 19.1 7/8 equals 22.2 1 equals 25.4 11/4 equals 31.8 11/2 equals 38.1 3 equals 76.2 32/16 equals 79.4 36/16 equals 85.7 38/16 equals 88.9 310/16 equals 92.1 313/16 equals 96.8 314/16 equals 98.4 315/16 equals 100.0 42/16 equals 104.8 45/16 equals 109.5 48/16 equals 114.3 412/16 equals 120.7 5 equals 127.0