What is the soundex?

With the digital age, the soundex is almost extinct.

However, if you ever search census records using microfilm it is still good to know.

census records

In essence the soundex is a phonetic algorithm for indexing names by sound, as pronounced in English.  The Soundex was developed by Robert C. Russell and Margaret King Odell and patented in 1918 and 1922.

The National Archives began indexing US Census Records in 1880.

The Soundex Code came to prominence in the 1960s when articles were published about the system.

This system is great in helping to find variation on a name.


Soundex codes begin with the first letter of the surname followed by a three-digit code that represents the (first three) remaining consonants.

A Soundex converter can do the tricky work for you and capture the nuances of the coding scheme (such as coding adjacent like letters as one). Enter above the surname that you want coded.

Soundex Coding Guide

Soundex code

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

The letters A,E,I,O,U,Y,H, and W are not coded.

Note that surname prefixes such as van, Von, Di, de, le, D’, dela, or du are sometimes disregarded in alphabetizing and in coding.


Alexander                   A425

Cunningham                C552

Davis                           D120

Jones                           J520

Williams                      W452

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