We have found that it all averages out.  Most people send in a mixture of small and large knives, and it is so much simpler this way than charging  $3.50 for a 4” knife and $7.00 for a 10” knife.  No measuring, no calculating, all you have to do is add up how many knives you have.  (If you have specialty knives, custom sporting knives, etc., call or email for pricing.)