List Difference Tool
Compare two lists in your browser to find items unique to List A (A minus B), items unique to List B (B minus A), and common items.
Open toolList Intersection Tool
Paste List A and List B into the List Intersection Tool below to extract shared items (A n B), measure Jaccard overlap and list coverage percentages, and export the matched list.
Free to useNo sign-upRuns in your browser
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Enter the inputs, then select Find Intersection.
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How List Intersection Tool works
The List Intersection Tool splits both inputs by your chosen delimiter, trims whitespace, normalizes keys by your case rule, and retains only elements present in both sets.
Intersection (A n B) = {x in Unique(A) : x in Unique(B)}; Jaccard Overlap = |A n B| / |A U B|.
In addition to the Jaccard index, the tool calculates coverage of List A (|A n B| / |A|) and coverage of List B (|A n B| / |B|).
List Intersection Tool Quick Reference & Input Guide
Review the input parameters, allowed value ranges, and worked reference cases for the List Intersection Tool below before running your calculation.
| Parameter / Scenario | Default / Sample Value | Rule or Allowed Range | Output / Usage Note |
|---|---|---|---|
| Input: List A | sku-101 sku-102 sku-104 sku-108 s... | First list of items (newline or comma separated). | Required workspace parameter |
| Input: List B | sku-102 sku-105 sku-108 sku-110 s... | Second list of items to intersect with List A. | Required workspace parameter |
| Input: Item delimiter | newline | Options: One item per line (Newline), Comma or newline separated | Required workspace parameter |
| Input: Case matching | insensitive | Options: Case-insensitive (SKU-102 == sku-102), Case-sensitive (exact character match) | Required workspace parameter |
| Worked Case 1: Warehouse SKU overlap (5 SKUs in A vs. 5 SKUs in B) | Preloaded / test values | Intersection = Unique(A) n Unique(B); Jaccard Similarity = |A n B| / |A U B| * 100% | Intersecting [sku-101, sku-102, sku-104, sku-108, sku-110] with [sku-102, sku-105, sku-108, sku-110, sku-112] returns 3 shared SKUs (sku-102, sku-108, sku-110), 60.00% coverage of each list, and 42.86% Jaccard overlap (3 of 7 unique SKUs). |
| Worked Case 2: Competitor keyword overlap audit | Preloaded / test values | Intersection = Unique(A) n Unique(B); Jaccard Similarity = |A n B| / |A U B| * 100% | Paste two domain keyword exports in Case-insensitive mode to isolate shared ranking queries and calculate what percentage of your keyword portfolio overlaps. |
How to use List Intersection Tool step by step
Prepare your two lists of keywords, SKUs, domains, or user IDs and run the intersection check.
Paste List A and List B
Paste your primary list into List A and the comparison list into List B.
Select delimiter and case sensitivity
Choose Newline or Comma separation and set Case-insensitive or Case-sensitive matching.
Calculate intersection and export matches
Click Find Intersection to view the shared item count, Jaccard similarity, and clean matched list ready to copy or download.
Worked examples for List Intersection Tool
Explore two practical intersection checks for inventory SKUs and keyword overlap.
Warehouse SKU overlap (5 SKUs in A vs. 5 SKUs in B)
Intersecting [sku-101, sku-102, sku-104, sku-108, sku-110] with [sku-102, sku-105, sku-108, sku-110, sku-112] returns 3 shared SKUs (sku-102, sku-108, sku-110), 60.00% coverage of each list, and 42.86% Jaccard overlap (3 of 7 unique SKUs).
Competitor keyword overlap audit
Paste two domain keyword exports in Case-insensitive mode to isolate shared ranking queries and calculate what percentage of your keyword portfolio overlaps.
Comma-separated tag intersection
Switch the delimiter to 'Comma or newline separated' to compare comma-delimited tag strings directly without converting commas to line breaks.
How to interpret the List Intersection Tool output
Compare Jaccard overlap against individual list coverage percentages when lists have very different sizes.
If List A has 10 items and List B has 1,000 items, and all 10 items from A appear in B, the Jaccard similarity is only 1.00% (10 / 1,000), whereas List A coverage is 100.00%. Reviewing both metrics shows whether one list is a subset of the other.
Input limits, assumptions, and related tools
Check delimiter and case settings before exporting matched records.
Both lists must contain at least one non-empty item. Internal duplicates within List A or List B are collapsed before set intersection is computed. To see items that did not match, use the List Difference Tool; to combine both lists without duplicates, use the List Union Tool.
List Union Tool
Combine and deduplicate two lists into a single set union (A U B), preserve first-seen or alphabetical order, and track duplicates removed.
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Open toolList Intersection Tool: common questions
Answers about using List Intersection Tool and understanding its results.
What does the List Intersection Tool calculate?
It extracts every unique element that appears in both List A and List B (the mathematical intersection A n B), along with the overlap percentage relative to List A, List B, and the combined union (Jaccard index).
What is Jaccard similarity percentage?
Jaccard similarity divides the number of shared items |A n B| by the total number of unique items across both lists |A U B|. A 100% Jaccard score means the two unique sets are identical.
Can I intersect comma-separated lists as well as line-by-line lists?
Yes. Switch Item delimiter to 'Comma or newline separated' to parse inline CSV values, tags, or ID lists without reformatting them first.
Which list controls the order of the intersection output?
Matched items are output in the exact order they first appear in List A.
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