Levenshtein Distance Calculator
Free online Levenshtein distance calculator. Measure the edit distance and similarity ratio between two strings instantly. 100% client-side.
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What is Levenshtein Distance Calculator?
The Levenshtein Distance Calculator is a free, client-side tool that measures how similar two pieces of text are. It reports the minimum number of single-character edits (insertions, deletions, and substitutions) needed to turn one string into the other, along with a similarity percentage, a Hamming distance when lengths match, an operation breakdown, a character alignment, and the full dynamic-programming matrix.
Key Benefits
- See Levenshtein distance and a 0–100% similarity ratio update live as you type
- Understand the difference with matches, substitutions, insertions, and deletions counted separately
- Visualize the edit path with a color-coded character alignment and shaded DP matrix
- Handle messy real-world data with case-insensitive and whitespace-normalization options
- Keep data private — everything runs locally in the browser with no server calls
Common Use Cases
- •Build fuzzy matching, autocomplete, or spell-checking features during development
- •Find near-duplicate product names, addresses, or user records for data cleaning
- •Teach or learn the classic Levenshtein dynamic-programming algorithm visually
- •Compare log messages, error strings, or command output to cluster similar entries
- •QA string transformations to verify that output stays within an expected edit distance
How to Use the Levenshtein Distance Calculator
- Enter both strings: Type or paste your two strings into the String A and String B boxes. Results update live as you type.
- Choose options: Optionally enable Case insensitive or Ignore extra whitespace to match how real-world text is compared.
- Read the results: Check the Levenshtein distance, similarity percentage, Hamming distance, and the counts of matches, substitutions, insertions, and deletions.
- Inspect alignment & matrix: Review the color-coded character alignment and, for short strings, the shaded DP matrix. Click Copy to save the summary or Swap to reverse the inputs.
Key Features
- Instant Levenshtein (edit) distance and a 0–100% similarity ratio between any two strings, computed live as you type
- Operation breakdown showing matches, substitutions, insertions, and deletions so you see exactly what changed
- Color-coded character alignment that maps each position from String A to String B, with gaps marked clearly
- Interactive dynamic-programming matrix with shaded cells, rendered automatically for short strings
- Case-insensitive and whitespace-normalization toggles for comparing real-world, messy text
- 100% client-side and offline — no server calls, no tracking, and Hamming distance included when lengths match
Frequently Asked Questions
What is Levenshtein distance?
Levenshtein distance is the minimum number of single-character edits (insertions, deletions, and substitutions) needed to transform one string into another. A distance of 0 means the strings are identical.
How is the similarity percentage calculated?
The similarity ratio is (1 - distance / max(length A, length B)) × 100. Two identical strings score 100%, while a tiny string versus a very long one approaches 0%.
Why is the Hamming distance sometimes shown as a dash?
Hamming distance only compares characters position by position, so it is only defined when both strings have equal length. When lengths differ, it is omitted and a note is shown.
Is my text sent to a server?
No. All computation happens entirely in your browser using JavaScript. Nothing is uploaded, logged, or stored, and the tool works fully offline.