similarity.openverbs.com

Levenshtein edit distance (insertions, deletions, substitutions) between two strings, plus a normalized similarity in [0,1]. Operates on Unicode code points.

Damerau-Levenshtein distance — like Levenshtein but also counts adjacent transpositions as a single edit — plus a normalized similarity in [0,1].

Hamming distance — the number of positions at which two EQUAL-LENGTH strings differ — plus a normalized similarity. Strings of unequal length are a clean 400.

Jaro similarity and the Jaro-Winkler variant (which boosts scores for a shared prefix), both in [0,1]. The prefix boost factor is configurable (default 0.1, max 0.25). Well suited to short strings like names.

Sørensen-Dice similarity coefficient in [0,1] over character bigrams — robust to word order and minor edits.

Jaccard similarity index in [0,1] — the size of the intersection over the union of the two strings' character-bigram sets.

Encode a word with the classic Soundex algorithm (letter + 3 digits) for phonetic matching of names.

Encode a word with the Metaphone algorithm — more accurate than Soundex for English pronunciation.

Encode a word with Double Metaphone, returning a primary and a secondary code to capture alternate pronunciations (useful for non-English names).

Report whether two tokens sound alike under a chosen algorithm (soundex, metaphone or double-metaphone; default double-metaphone). Returns each token's codes and a boolean match.