Compare Two Lists Online
Paste two lists below and instantly see which items are only in the first list, only in the second, or in both. Line order does not matter, duplicates are handled automatically, and everything runs inside your browser — nothing you paste is uploaded or stored.
How it works
The tool reads each box as a list with one item per line. It then treats each list as a set — a collection of unique items where position is irrelevant — and compares the two. That gives you three answers at once: the items that appear only in List A (these were removed, missing, or unique to the first list), the items that appear only in List B (these were added or unique to the second list), and the items that appear in both lists (the overlap, or intersection).
Before matching, you can adjust how strict the comparison should be. Trim spaces removes
leading and trailing whitespace so "apple " and "apple" are treated as the same.
Ignore blank lines skips empty rows that often sneak in when you copy from a spreadsheet.
Ignore upper/lower case makes Grapes match grapes, which is handy
for emails and names. Sort results A–Z orders each output panel alphabetically so the
differences are easy to scan.
Examples of what you can do
| You have… | Put in List A | Put in List B | "Only in" tells you… |
|---|---|---|---|
| Two email exports | Last month's subscribers | This month's subscribers | Who unsubscribed (only in A) and who joined (only in B) |
| An inventory check | System stock list | Physically counted items | What is missing or mis-recorded |
| Two spreadsheets | Column from sheet 1 | Column from sheet 2 | Rows that don't reconcile |
| Code or config | Allowed values | Values actually used | Unexpected or undefined entries |
Why this is not the same as a text diff
A traditional text "diff" compares two blocks line by line, in order. If you move one line to the
top, a diff marks everything as changed. That is perfect for source code, but wrong for lists, where
cat, dog, fish and fish, cat, dog are really the same set. This tool ignores order and
focuses on membership: is each item present or not? If you specifically need an order-aware comparison, read
set difference vs. text diff to choose the right approach.
Frequently asked questions
How do I compare two lists to find the differences?
Paste one list into List A and the other into List B, one item per line. The three result panels update as you type: Only in List A, In both lists, and Only in List B. Toggle the options to control trimming, blank lines and case sensitivity.
Is my data uploaded anywhere?
No. The comparison happens entirely in your browser with JavaScript. Nothing is sent to a server, so it is safe for confidential lists like customer emails or internal IDs.
Does the order of lines matter?
No. Each list is treated as a set, so the same items in a different order still match. The tool compares membership, not position.
How are duplicates handled?
Repeated lines inside one list are collapsed to a single entry, and the summary reports how many duplicates were ignored. Each result shows every unique item once.
Is there a size limit?
No fixed limit. Because it runs locally, tens of thousands of lines compare almost instantly on a typical computer.
New to this kind of comparison? The step-by-step guide walks through a real example from start to finish.