Why this tool is useful
Use this metric when neighbouring key swaps should count as one likely typing error while repeated edits to the same substring are intentionally restricted.
Text & List Tools · runs locally
Damerau–Levenshtein OSA Distance Calculator
Measure edits with insertion, deletion, substitution and one adjacent transposition per substring using the explicit OSA variant.
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How it works
A bounded dynamic-programming matrix evaluates ordinary edits plus adjacent transpositions and labels the result as optimal string alignment rather than unrestricted Damerau distance.
Practical example
The reversed neighbours ca and ac have OSA distance 1 because one adjacent transposition connects them.
Validation
The calculation is deterministic and explains validation errors instead of silently changing invalid input.
Privacy boundary
Input and output remain in this tab. Copy and download happen through browser APIs without a server upload.
Result passport
Every run reports its tool mode, timestamp and input/output size so transformed data can be audited.