Soundex -- What It Is and How to Use It
As you may know, most last names can be spelled in a variety of ways. For example, "Smith" can also be spelled "Smyth," "Smithe," and "Smythe." This is one of the reasons why the Works Progress Administration created Soundex in the late 1930's. Soundex is a method of giving names sound codes. It is important to understand because it is used by the United States government to index the surnames of some of the United States census records. By grouping together last names that sound similar, Soundex allows people to search for ancestors, even when the surname may have been recorded in any of several different spellings. The 1880, 1900, 1910, and 1920 censuses have Soundex indexes, but there are limitations. The 1880 census is only indexed for families with children under 10 years old. In addition, the 1910 census is only indexed for the following states: Alabama, Arkansas, California, Florida, Georgia, Illinois, Kansas, Kentucky, Louisiana, Michigan, Mississippi, Missouri, North Carolina, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Texas, Virginia, and West Virginia.
To use the Soundex index, you must first create the code for your surname. Each Soundex code consists of one letter and three numbers, such as G616, no matter how long the name is. The letter is always the first letter of the surname. For example, "S" for "Smith." However, if the surname has a prefix, such as De, De la, Di, La, Le, Van, or Von, figure out the codes for the name both with and without the prefix -- it may be listed under either code. (Please note that Soundex does not consider Mc and Mac prefixes.) The numbers in the code are determined by the rest of the consonants in the name, and the vowels are always ignored. The table below shows you how to substitute the numbers for the letters in your name. Be sure to read the special rules below the table.
Convert these letters to the number listed:
- 1 = B, F, P and V
- 2 = C, G, J, K, Q, S, X and Z
- 3 = D and T
- 4 = L
- 5 = M and N
- 6 = R
- Remove these letters: A, E, I, O, U, Y, W, H
Let's do some examples.
Albright = A416. "A" for the first letter, "4" for the "l," "1" for the "b," and "6" for the "r." Since there are now three numbers in the code, the remaining letters in the name are discarded.
Greenbaum = G651. "G" for the first letter, "6" for the "r," ignore the two "e's," "5" for the "n," and "1" for the "b." Since there are now three numbers in the code, the remaining letters in the name are discarded.
Del Principe = D416 or P652. In the first case, "D" for the first letter, ignore the "e," "4" for the "l," "1" for the "P," and 6 for the "r." Since there are now three numbers in the code, the remaining letters in the name are discarded. In the second case, "P" for the first letter, because we're ignoring the prefix, "6" for the "r," ignore the "i," "5" for the "n," and "2" for the "c." Since there are now three numbers in the code, the remaining letters in the name are discarded.
Special Rules
Treat double letters as single letters.
- Heggenburger = H251. "H" for the first letter, ignore the "e," "2" for the "gg," ignore the "e," "5" for the "n," and "1" for the "b."
- Any letters next to each other that have the same number should be treated as one. This means that you should never have two of the same numbers next to each other in a Soundex code.
If the second letter has the same code as the first letter, ignore it.
- Blackman = B425. "B" for the first letter, "4" for the "l," ignore the "a," "2" for the "c," ignore the "k," because it would repeat the "2," "5" for the "m." This also applies to the first and second letters in the name.
- Schmidt = S530. "S" for the first letter, ignore the "c" because it would have the same code as the "S," ignore the "h," "5" for the "m," ignore the "i," "3" for the "d," ignore the "t" because it would have the same code as the "d," and then add a zero to the end since you've reached the end of the name without completing the code.
If there aren't enough valid letters in the name to create 3 digits after the first letter, add zeros.
- Lippmann = L150. "L" for the first letter, ignore the "i," "1" for the "pp," "5" for the "m," ignore the "a," ignore the "n" because it would repeat the "5," and then add a zero to the end since you've reached the end of the name without completing the code.
With your Soundex code in hand, you're ready to use the microfilm indexing system. Locate the roll containing the Soundex card index for the state in which your ancestor lived at the time of the census. The rolls are arranged by number, or sometimes the numbers are grouped and then arranged alphabetically by the first name within each group. The Soundex card index will tell you which microfilm roll contains the actual census data for your ancestor. From there, you can get the correct roll and see the actual census records. A staff member where you are doing your research should be able to assist you in locating the correct rolls of microfilm.