US Bolts Size Chart

Sizes for Hex Bolts, Lag Bolts & Square Bolts in Inches

Refer to this chart to find the appropriate head size and corresponding wrench or socket size for hex bolts, heavy hex bolts, lag bolts, or square bolts. Regardless if you’re looking for a grade 2, 5 or 8 hex bolt, the dimensions will be identical and the difference lies only in the material.

Bolt Diameter (in) Head, Wrench & Socket Size
Hex Bolt, Lag Bolt, Square Bolt Heavy Hex Bolt
#6 1/4  
#8 1/4  
#10 5/16  
#12 5/16  
1/4 7/16 or 3/8  
5/16 1/2  
3/8 9/16  
7/16 5/8  
1/2 3/4 7/8
9/16 13/16  
5/8 15/16 1 1/16
3/4 1 1/8 1 1/4
7/8 1 5/16 1 7/16
1 1 1/2 1 5/8
1 1/8 1 11/16 1 3/4
1 1/4 1 7/8 2
1 3/8 2 1/16  
1 1/2 2 1/4  

 

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