How do I find the people on both lists?

Paste roster A in the left box and roster B in the right box, one name per line, then read the In both panel — that is the intersection, everyone who shows up on both. Example: A holds Anna, Bob, Cara and B holds Bob, Cara, Dan, so In both shows Bob and Cara. Turn on Ignore case if one sheet wrote bob and the other Bob, otherwise they count as two different people and miss each other.

How do I get items that are only in list A and not in list B?

Look at the Only in A panel. It keeps every line from A whose value never appears anywhere in B, which is the set difference A minus B. Example: A is apple, pear, plum and B is pear, plum, kiwi, so Only in A is just apple. Only in B does the mirror image (kiwi here). This is the fast way to spot what you removed or what the other team is missing.

What does ignore case actually change?

With Ignore case on, Gmail.com and gmail.com are treated as the same item, so they land in In both instead of being split across Only in A and Only in B. The panels still display the original text you pasted, the change is only in how two lines are matched. Leave it off when case carries meaning, such as case-sensitive passwords, file paths on Linux, or programming identifiers where Total and total are genuinely different.

How is this different from a text diff tool?

A text diff compares two blocks line by line in order and highlights inserts, deletes and edits where they sit, so moving a line counts as a change. This tool treats each list as a set: order is ignored and the same value appearing twice still counts once. Example: list A then B reversed produces zero differences here but a wall of red and green in a diff. Use a diff to review edits to one document, use this to compare two membership lists.

Does the order of lines matter?

No. Comparison is by membership, not position, so apple, banana, cherry and cherry, apple, banana give identical results — both lists hold the same three items. Within each output panel items keep the order they first appeared in their source list so the result stays readable. If you care about line-by-line position rather than membership, you want a diff tool instead, not this set comparison.

What happens to duplicate and blank lines?

A value repeated inside one list still counts as a single member, so apple, apple, pear behaves like apple, pear when comparing. The Merged (union) panel is always duplicate-free across both lists. Blank lines are skipped by default via Ignore blank lines so stray empty rows from a copy-paste do not become a phantom shared item; turn that option off if an empty string is genuinely meaningful data you want to compare.

Reconcile two email or subscriber lists

You exported subscribers from the old CRM and the new one and need to know who is on both, who only the old system had, and who is new. Paste each export, turn on Ignore case and Trim, and the panels hand you the three groups instantly. Copy Only in A to re-import the people the migration dropped, copy Merged to seed a clean combined list with no duplicates.

Diff two columns from a spreadsheet

Copy one column of SKUs, order IDs or usernames out of a sheet, paste it as list A, paste yesterday's column as list B. In both is the rows that carried over, Only in A is what got added today, Only in B is what disappeared. No VLOOKUP, no formula, no sending company data to a server — it is faster than wiring up a spreadsheet match.

Compare installed packages or dependencies

Run a package list on two machines or two environments and paste the output into both boxes. Only in A shows what is installed here but missing there, In both is the shared baseline, Merged is everything you would need to provision a third box. Trim handles the stray indentation that command output loves to add.

Audit access or permission lists

Compare who currently has access to a system against the list of who should, and the gaps fall out: Only in A is people with access who are not on the approved list, Only in B is approved people still waiting. It turns a tedious eyeball check into a copyable report you can paste straight into a ticket.

List Comparison: Compare Two Lists Online

Compare two lists line by line: only in A, only in B, in both, and merged — all in your browser

Runs locally
Category Text
Best for Removing repetitive cleanup work from everyday writing and operations.

Ignore caseTrim each lineIgnore blank lines

List A (0 items)

List B (0 items)

Only in A 0 items

Only in B 0 items

In both 0 items

Merged (union) 0 items

What this tool does

Free online list comparison tool. Paste two lists, one item per line, and it instantly splits them into four buckets: items only in list A, items only in list B, items in both (the intersection), and the merged duplicate-free union. Each bucket shows its own count and has a one-click copy button, so you can lift "the names on both rosters" or "the SKUs we dropped" straight into a spreadsheet or email. Toggle ignore case, trim each line and skip blank lines to control exactly how two items count as equal. This is set math on lines, not a character diff: order does not matter and a line that appears twice in one list is still one member. It works the same on email lists, CSV columns, package names, user IDs or any Chinese and English text. Everything runs locally in your browser and the shareable link rebuilds both lists for the person you send it to. 100% client-side, nothing uploaded.

Tool details

Input: Text; The page exposes text boxes, numeric controls, file pickers, or structured inputs depending on the tool.
Output: Live result + Copy; The result area focuses on usable output, with copy, download, or preview actions when supported.
Privacy: Browser-side processing; The main tool logic does not call an external API, so inputs normally stay in the current tab.
Save / share: Shareable URL state; Key settings are encoded in the URL so another person can reopen the same setup.
Performance budget: Initial JS <= 9 KB; No WASM budget is declared, keeping the tool quick to open on mobile.
Best fit: Text · Developer; Category and role tags drive related tools, internal links, and quick fit checks.

How to use

1. Input

Paste or drop your content into the tool panel.
2. Process

Click the button. All processing is local in your browser.
3. Copy / Download

Copy the result or download to disk in one click.

How List Comparison fits into your work

Use it to clean, compare, reshape, or extract plain text before it goes into a document, CMS, spreadsheet, or prompt.

Text jobs

Removing repetitive cleanup work from everyday writing and operations.
Making text easier to compare, paste, publish, or feed into another tool.
Working with content locally when the text is private or unfinished.

Text checks

Scan for unintended whitespace, duplicate lines, and lost punctuation.
For long text, test the first few lines before applying the whole change.
Copy the final output only after checking the preview.

Good next steps

These links move the current task into a more complete workflow.

Real-world use cases

Reconcile two email or subscriber lists
You exported subscribers from the old CRM and the new one and need to know who is on both, who only the old system had, and who is new. Paste each export, turn on Ignore case and Trim, and the panels hand you the three groups instantly. Copy Only in A to re-import the people the migration dropped, copy Merged to seed a clean combined list with no duplicates.
Diff two columns from a spreadsheet
Copy one column of SKUs, order IDs or usernames out of a sheet, paste it as list A, paste yesterday's column as list B. In both is the rows that carried over, Only in A is what got added today, Only in B is what disappeared. No VLOOKUP, no formula, no sending company data to a server — it is faster than wiring up a spreadsheet match.
Compare installed packages or dependencies
Run a package list on two machines or two environments and paste the output into both boxes. Only in A shows what is installed here but missing there, In both is the shared baseline, Merged is everything you would need to provision a third box. Trim handles the stray indentation that command output loves to add.
Audit access or permission lists
Compare who currently has access to a system against the list of who should, and the gaps fall out: Only in A is people with access who are not on the approved list, Only in B is approved people still waiting. It turns a tedious eyeball check into a copyable report you can paste straight into a ticket.

Common pitfalls

Expecting a character-level diff. This tool does set math on whole lines, so a small typo inside a line makes it a completely different item rather than a highlighted edit. For reviewing edits within a single document, reach for a real diff tool instead.
Forgetting to turn on Ignore case when the two sources use different capitalization. With it off, Alice@x.com and alice@x.com split across Only in A and Only in B and never meet in the intersection, which quietly understates your overlap.
Leaving trailing spaces in pasted data. A line ending in a space does not match the same word without one unless Trim is on, so a clean-looking export can produce surprising Only in A and Only in B results. Keep Trim enabled for copy-pasted text.

Privacy

Both lists are compared by plain JavaScript running inside your browser tab. Nothing you paste is uploaded, logged or sent anywhere, so it is safe for customer emails, internal user IDs or any sensitive roster. One caveat: the shareable link encodes both lists in the URL so a recipient can reopen them, which means a link pasted into chat records that data in the other server's access log. For confidential lists, use the copy buttons and paste the results rather than sharing the URL.

FAQ

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List Comparison: Compare Two Lists Online

What this tool does

Tool details

How to use

1. Input

2. Process

3. Copy / Download

How List Comparison fits into your work

Text jobs

Text checks

Good next steps

Real-world use cases

Reconcile two email or subscriber lists

Diff two columns from a spreadsheet

Compare installed packages or dependencies

Audit access or permission lists

Common pitfalls

Privacy

FAQ

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