Soundex Limitations

  • Names that sound alike do not always have the same soundex code. For example, Lee (L000) and Leigh (L200) are pronounced identically, but have different soundex codes because the silent g in Leigh is given a code.

  • Names that sound alike but start with a different first letter will always have a different soundex code. Thus, names such as Carr (C600) and Karr (K600) have different soundex codes even though they sound alike. Name that sound alike but have different first letters should have each name calculated and searched for separately.

  • Since the soundex system is based on English pronunciationn, some European names may not soundex correctly. For example, some French surnames with silent last letters will not code according to pronunciation. An example is the French name such as Beaux - where the x is silent. While Beau (B000) is pronounced identically to Beaux (B200), they will have different soundex codes. This could be true of any surname that does not use English pronunciation.

  • Sometimes names that don't sound alike have the same soundex code. When I am searching for the surname Powers (P620), I have to wade through Pierce, Price, Perez and Park which all have the same soundex code. Yet Power (P600), from which many Irish Powers names originated, has a different soundex code.

  • Somestimes, surnames with prefixes were coded without the prefix, but not always. If you are searching for a surnames such as DiCaprio or LaBianca, you should try the soundex for both with and without the prefix.

  • US Census soundex confusion arises with names such as Ashcraft. When the original soundex coder didn't code the H and didn't consider the H as a separator between the adjacent letters with the same code S and C , then the S and C would be considered adjacent letters to be coded only once and the soundex will be A261. In the 1920 NY Census, Ashcraft is found under A261.

    Those who coded the soundex for the 1880*, 1900 and 1910** census may or may not have used this rule. They sometimes considered the H as a separator, and did not code the S and C as adjacent letters that would only be assigned one letter, but rather gave a number code to each letter. In this case Ashcraft would be A226, the result you receive with the calculator on this page.

    The important thing to know is that the US Census was not consistent with using the letter H and W as separators between adjacent letters. If you are trying to calculate the soundex for a name with the letters W or H that separate two adjacent letters, it is best to calculate the soundex using the two different methods to locate the name in the US census. This would be true of any name that has any of the letters C,S,G,J,K,Q,X,Z on both sides of the letter H or W such as SHC, SHS, CHS, KHZ, SWS, KWS, CWK.

  • A surname of more than one word, or a surname that commonly comes before a given name, such as Native Americans, Catholic nuns and Chinese surnames, may have been coded under the name which appears last, even though it might not be the actual surname. In the case of multi-word surnames, only the last word may have been coded.


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