Jaccard Similarity Calculator

Calculate Jaccard similarity

The Jaccard similarity index measures how alike two sets are by dividing the number of elements they share by the total number of distinct elements across both. This calculator treats each text as a set of unique words and computes the index, which ranges from zero for no overlap to one for identical sets. Two short texts sharing two of four distinct words have a Jaccard similarity of one half.

Because it works on sets, word order and repetition are ignored; only the presence of each distinct word matters.

Where Jaccard similarity is used

The Jaccard index is widely used in text analysis, document deduplication, recommendation systems and clustering, wherever you need a simple, interpretable measure of overlap. In natural language and retrieval work it helps compare keyword sets, tags and short passages. Its simplicity and clear range make it easy to threshold, for example flagging pairs above a chosen similarity as near-duplicates.

For tasks where word frequency or order matters, cosine similarity or edit distance may be more appropriate. All calculation happens locally in your browser.

Notes on these estimates

Because the jaccard similarity calculator runs entirely in your browser, nothing you enter is uploaded, so you can use it with private data safely. The figures are estimates based on the values you provide and common rules of thumb, so treat them as planning guidance rather than exact measurements, and run the tool as often as you need for free.

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