Most beads are measured in  
  millimeters. If you are not  
  familiar with millimeter sizes,  
  here are some conversions to help you.  

 

Approximate conversions:

 

1/4 inch = 6mm

 
  1/2 inch = 13mm  
  3/4 inch = 19mm  
  1 inch = 25mm  
  1 1/4 inch = 32mm  
  1 1/2 inch = 38mm