Calculate Structural Metric Bolt Lengths

This information is for a guide only, and has been used in the Australian steel fabrication industry.

Size \ Grade 4.6 8.8
M12 19 n/a
M16 23 27
M20 26 31
M24 31 37
M30 35 43
M36 N/A 49

Note: Chart only works with standard metric structural bolts, grade 4.6 or 8.8 nuts and hard flat washers.