← All tools

Soundex Encoder

Encode names with the Soundex phonetic algorithm, which reduces a name to a four-character code (one letter plus three digits) so that names that sound alike share the same code — the basis of the US census's surname indexing since 1880. Robert, Rupert, and Ruben all encode to R163; Ashcraft to A261. Use it for fuzzy name matching, deduplication, and genealogy lookups. Paste a list of names (one per line) for batch encoding, or check whether two names are phonetically alike. Everything runs locally in your browser.

Names (one per line)

Codes

Step trace (first name)

Phonetic match

Name A
Name B

Soundex (Knuth, The Art of Computer Programming vol. 3) maps a name to a letter followed by three digits. Consonants are coded: B/F/P/V→1, C/G/J/K/Q/S/X/Z→2, D/T→3, L→4, M/N→5, R→6. Vowels (A,E,I,O,U,Y) act as separators that break runs of equal-coded consonants; H and W are transparent — they do not break such runs (the US National Archives census rule, which is why Ashcraft → A261: the S and C, both code 2, are separated by H and so merge into a single 2). The first letter is kept and its code seeds the run, so an immediately following same-coded consonant collapses (Pfister → P236: the F, code 1 like P, is absorbed). Adjacent equal codes collapse to one; the result is truncated or zero-padded to four characters. Two names that share a Soundex code are considered phonetically equivalent — useful for matching misspelled or variant names. Pairs with the Phonetic-alphabet and String Similarity tools. Everything runs locally — nothing leaves your browser.