Daily AncestorSoundex calculator
Soundex turns a surname into a letter and three digits by how it sounds, so Smith, Smyth, and Schmidt all become S530 and file together in the old census indexes.
Census takers spelled names the way they heard them, and families spelled their own names more than one way. Soundex was built to get around that. It codes a surname by its consonant sounds, so spellings that sound alike land under the same code.
The National Archives still holds Soundex indexes for several censuses, and many search sites still let you search by Soundex. Type a surname here to get its code.
How to use it
- Type the surname only, without first names or titles.
- Read the code: the first letter of the name followed by three digits.
- If the name has a prefix such as Van, De, Di, La, or Le, also code it without the prefix and search under both codes.
- Use the code with the state of residence to find the right index reel or to widen a search online.
Worked examples
Ashcraft
Soundex code: A261
S is 2 and C would also be 2. They are separated only by H, and the H and W rule says the C is then skipped. R is 6 and F is 1.
Tymczak
Soundex code: T522
M is 5, then C and Z both code to 2 and count once. The A between Z and K is a vowel, so K is coded again as 2.
Schmidt
Soundex code: S530
C after S has the same digit and is dropped, H is ignored, M is 5, D is 3, and a zero fills the last place. Smith and Smyth give the same code.
Deusen (VanDeusen without the prefix)
Soundex code: D250
The National Archives advises coding prefixed names both ways. VanDeusen with the prefix codes as V532.
The American Soundex rules
Keep the first letter of the surname. Then turn the following consonants into digits: B, F, P, V are 1; C, G, J, K, Q, S, X, Z are 2; D, T are 3; L is 4; M, N are 5; R is 6. Skip A, E, I, O, U, H, W, and Y. Stop at three digits, and add zeros if the name runs out first, so Lee becomes L000.
Double letters count once, as do neighboring letters with the same digit, so Pfister is P236 and Jackson is J250. A vowel between two letters with the same digit keeps them separate, so both are coded. An H or W between them does not, so the second is skipped.
Names with a prefix such as Van, Con, De, Di, La, or Le may be filed either way, so check both codes. Mc and Mac are not treated as prefixes: McDonald is coded from the M.
Which census indexes use Soundex
The 1880 Soundex covers only households with a child aged 10 or younger. The 1900 and 1920 indexes cover every state. The 1910 index covers 21 states, mostly in the South and Midwest, plus California and Pennsylvania. The 1930 index covers ten Southern states and a few counties in Kentucky and West Virginia.
The cards were filmed by state, then by Soundex code, and within each code alphabetically by the first name of the head of household. To use them you need the surname and the state where the family lived on census day, and it helps a great deal to know the head of household's first name, because the family is filed under that name. Each card gives the county, the town, and the volume, enumeration district, sheet, and line numbers that lead you to the census page itself.
Questions people ask
What is Soundex in genealogy?
A way of indexing surnames by sound rather than spelling. Each name becomes a letter and three digits, so variant spellings of one name are filed together.
How do I find my Soundex code?
Type the surname into the calculator above. By hand: keep the first letter, code the next consonants by the table, skip vowels, H, W, and Y, and pad with zeros to four characters.
Why is the first letter not a number?
Soundex keeps the first letter as written. That is also its weak spot: Kane and Cane get different codes, so search under each first letter a clerk might have heard.
Which censuses have a Soundex index?
1880 (households with young children only), 1900 and 1920 (all states), 1910 (21 states), and 1930 (ten Southern states and parts of Kentucky and West Virginia).
How to cite this page
Daily Ancestor. "Soundex calculator." Tools. https://dailyancestor.com/tools/soundex-calculator. Last checked 2026-10-15.