||Using the Sound Coding Index
- To find an individual name among the millions listed in the 1880, 1900, 1910, and 1920
censuses, you will use an indexing and filing system called the Soundex. The Soundex is a
coded surname (last name) index based on the way a surname sounds rather than the way it
is spelled. Surnames that sound the same but are spelled differently, like Smith and
Smyth, have the same code and are filed together. The Soundex coding system was developed
so that you can find a surname even though it may have been reorded under various
- To search for a particular surname, you must first work out its code. Every Soundex code
consists of a letter and three numbers, like S650. The letter is always the first letter
of the surname. The numbers are assigned to the remaingin letters of the surname according
to the Soundex coding guide.
Soundex Coding Guide
||represents the letters
||B P F V
||C S K G J Q X Z
Disregard the letters A, E, I, O, U, W, Y, and H.
- Most surnames can be coded using the following four steps. (For names with prefixes,
double letters or letters side by side that have the same number on the Soundex coding
guide, see "Additional Rules".)
||On line 1, write the surname you are coding, place one letter in each
||On line 2, write the first letter of the surname in the first box.
||On line 1, disregarding the first letter, slash through the remaining
letters A, E, I, O, U, W, Y, and H.
||On line 2, write the numbers found on the Soundex Coding Guide for the
first three remaining unslashed letters. Add zeros to any empty boxes. Disregard any
- Examples of Soundex-Coded Names
- Additional Rules
- Names With Prefixes
- If your surname has a prefix - like Van, Von, De, Di, or Le - you should code it both
with and without the prefix because it might be listed under either code. The Surname
VanDevanter, for example, should be coded in the two ways shown. (Mc and Mac aer not
- Names With Double Letters
- If your surname has any double letters, they should be treated as one letter. Thus, in
the surname Lloyd, the seond L should be slashed out; in the surname Guiterrez, the second
R should be slashed out.
- Names With Letters Side By Side That Have the Same Number On the
Soundex Coding Guide
- Your surname may have different letters that are side by side and have the same number
on the Soundex Coding Guide: for example, PF in Pfister (1 is the number for both P and
F); CKS in Jackson (2 is the number for C, K, and S). These letters should be treated as
one letter. Thus, in the name Pfister,F should be slashed out; in the name Jackson, K and
S should be slashed out.
- Names of Native Americans, Asians, and Nuns
- Researchers using the Soundex system to locate nuns, or persons with native American or
Asian names should be aware of the way such names are coded. Variations in coding differ
from the normal coding system.
- Phonetically spelled Asian and Native American names are sometimes coded as one
continuous name, or, if a distinguishable surname is given, the names are coded in a
normal manner. For example, the Native America name Shinka-Wa-Sa may be coded as
"Shinka" (S520) or "Sa" (S000). researchers should investigate the
various possibilities of coding such names.
- Nun names are coded as if "Sister" was their surname, and they appear in each
State's Soundex under the code "S236". Within the State's Soundex Code S236, the
names are not necessarily in alphabetical order.
- If several surnames have the same code, the cards for them are arranged alphabetically
by given name. There are divider cards showing most code numbers, but not all. For
instance, one divider may be numbered 350 and the next one 400. Between the two divider
cards there may be names coded 353, 350, 360, 365, and 355, but instead of being in
numerical order they are interfiled alphbetically by given name.
With your ancestor's name correctly coded, you are ready to use the
microfilmed Soundex card index, which is organized by state, and thereunder Soundex code
number, and thereunder alphabetically by first name or intial. There are four types of
index cards. The information you should copy from each is on the next page.
Compiled by the History and Genealogy Department
1301 Olive Street
St. Louis, Missouri, 63103
Revised August 1997, Reprinted July 1995
Back to the History and Genealogy Department
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