Size Conversion Info

1 mm = approximately 1/32"             
2 mm = approximately 1/8"                   
3 mm = approximately 1/8"                    
4 mm = approximately 3/16"                  
5 mm = approximately 3/16"                    
6 mm = approximately 1/4"                    
7 mm = approximately 1/4"                   
8 mm = approximately 5/16"                
9 mm = approximately 3/8"                   
10 mm = approximately 3/8"              
11 mm = approximately 7/16"           
12 mm = approximately 1/2"             
13 mm = approximately 1/2"             
14 mm = approximately 9/16"          
15 mm = approximately 5/8"                 
16 mm = approximately 5/8"             
17 mm = approximately 11/16"         
18 mm = approximately 3/4"             
19 mm = approximately 3/4"             
20 mm = approximately 13/16"       


For comparison:

Dime = 17mm

Penny = 19mm

Nickel = 21mm

Quarter = 24mm