Understanding the Soundex Code
The Soundex numeric code is designed to help overcome variations in spelling, and certain errors in transcription. The Soundex code is applied only to surnames, and is based on the progression of consonants in the name, rather than the spelling of the name. Having an understanding of the Soundex code can be a tool of great value. In the following example, we'll code the surname "Flagsmann," because it works well with each step of the illustration:

1. First, only specific consonants are coded. W, H, and Y are NOT coded, and neither are vowels. Remember "WHY vowels" (w, h, y, a, e, i, o, and u) and you'll remember the letters that are not coded.
   
   
2. Next, remove the non-coded letters from the surname ("WHY vowels").
   

   FLAGSMANN becomes FLGSMNN

   
   
3. Treat any double letters as though they were a single letter.
   

   FLGSMNN becomes FLGSMN

   
   
4. Review the Soundex coding guide:
   

   Soundex Code Guide

   Code Key Letters and Equivalents 1 = B, P, F, V 2 = C, S, K, G, J, Q, X, Z 3 = D, T 4 = L 5 = M, N 6 = R

   
   
5. Some names have two adjacent letters that have the same Soundex code number. Remove the second letter—but only if the original letters were not separated by a vowel:
   

   FLGSMN becomes FLGMN

   
   (The "G" and "S" both have a Soundex code of 2, so remove the "S". The "M" and "N" both have a Soundex code of 5, but were originally separated by a vowel. Leave them as they are.)
   
   
6. Substitute each of the remaining letters (except for the first letter, which always begins the Soundex code) for the corresponding Soundex code number:
   

   FLGMN becomes F 4255

   
   
7. Trim the end off of the coded sequence, until only four digits remain (one letter, followed by three numbers):
   

   F 4255 becomes F 425