usefmtly

List Compare

List Compare — Free online list comparison tool. Paste two lists and instantly see items only in List A, items only in List B, and items in both. Includes a Jaccard similarity score. No signup required.

0%
0List A
0Only A
0In both
0Only B
0List B
List A
List B
Only in A0

Paste a list above

In both0

Paste a list above

Only in B0

Paste a list above

Options

How to compare two lists

  1. Paste List A into the first input box — one item per line.
  2. Paste List B into the second input box — one item per line.
  3. Read the results — three colour-coded columns appear instantly: items only in A (orange), items in both (green), and items only in B (blue).
  4. Check the similarity score in the toolbar — a Jaccard percentage showing how much the two lists overlap.
  5. Copy any column using the copy icon in its header to grab just the section you need.

What the similarity score means

The similarity percentage is the Jaccard similarity coefficient — the number of items in common divided by the total number of unique items across both lists. It is one of the most widely used metrics for comparing sets in data science and information retrieval.

100% Identical lists — every item appears in both.
75–99% High overlap — minor additions or deletions between versions.
40–74% Moderate overlap — significant differences worth reviewing.
15–39% Low overlap — mostly different lists with some shared items.
0–14% Very different — almost no items in common.

Common use cases

SEO keyword gap analysis

Compare your keyword list with a competitor's to find keywords they rank for that you don't, and vice versa.

Mailing list changes

Compare this month's subscriber export with last month's to find new subscribers (only in B) and churned subscribers (only in A).

Permission audit

Compare two access control lists to find who has access in one system but not another.

Product feature comparison

Compare feature lists across two products or two versions to identify what each has that the other lacks.

Data migration check

After migrating records, compare source IDs with destination IDs to find any that were missed (only in A) or added (only in B).

Tag or label consistency

Compare tags applied in two systems to find inconsistencies or missing taxonomy terms.

📖 Further reading: How to Compare Two Lists — Guide or turn both lists into one clean output with Merge Lists

Frequently Asked Questions

How do I compare two lists?

Paste List A into the first box and List B into the second box with one item per line. As soon as both lists are present, the tool separates entries into Only in A, In Both, and Only in B. That makes it easy to audit overlaps, find missing values, and copy just the exact section you need for follow-up work.

What does the similarity percentage mean?

The similarity score is the Jaccard similarity coefficient — the number of common items divided by the total number of unique items across both lists. A score of 100% means the lists are identical. 0% means they share no items. 50% means half of all unique items appear in both lists.

Is the comparison case-sensitive?

No — by default the comparison is case-insensitive, so "Apple" and "apple" count as the same item. That is usually what you want for names, emails, tags, and keyword lists. If capitalization matters in your workflow, turn on the Case-sensitive toggle and the tool will treat differently cased entries as separate values.

What if an item appears multiple times in one list?

The comparison treats each list like a set, so repeated entries inside the same list do not increase the overlap or the unique counts. In other words, an item is either present or absent. If you want cleaner source data before you compare, run each list through Duplicate Line Remover first and then paste the de-duplicated versions here.

What are practical uses for list comparison?

List comparison is useful anywhere you need to spot overlap and gaps quickly. Teams use it to compare keyword exports from SEO tools, audit subscriber changes between months, find users missing from a permissions list, check product requirement differences, reconcile inventory exports, and review tag or category overlap across large content sets without doing the work manually.

Can I copy individual result sections?

Yes. Each result column — Only in A, In Both, and Only in B — has its own copy button, so you can grab exactly the segment you need without exporting everything. That is handy when you want to send only the missing items to a teammate, move shared entries into another tool, or save a clean diff for later review.

Related Tools

Merge ListsFree online list merger. Combine two lists, merge spreadsheet columns or CSV exports, remove duplicates, find overlap, interleave rows, and copy one clean output. No signup required.Duplicate Line RemoverFree online duplicate line remover. Paste any list and remove duplicate lines instantly. Case-insensitive or case-sensitive, keep first or last occurrence, or highlight duplicates instead. No signup required.Alphabetical Order SorterFree online alphabetical sorter. Sort lists A–Z or Z–A, by length, or with natural sort. Remove duplicates, trim whitespace, and sort comma or semicolon-separated lists too. No signup required.Split ListFree online list splitter. Split text into a list by any delimiter — comma, semicolon, newline, space, tab, or custom. Trim items, remove blanks, number the results. Instant, client-side.List to Comma SeparatedConvert a line-by-line list to comma-separated values (CSV), semicolons, pipes, or any custom delimiter. Add quotes, trim whitespace. Free — no signup required.