List Comparator

List Comparator is a free tool that runs entirely in your browser, with no data ever sent to a server. Compare two lists to see what they share and what sets them apart.

What it's for

Find the customers common to two exports, check what changed between two versions of a task list, or spot duplicates between two files.

What this tool does not do

This tool only applies the transformation described, with no spellchecking and no interpretation of the text's meaning. A text of several tens of thousands of lines processes instantly; beyond that, the only limit is your device's memory.

Frequently asked questions

Is the line order kept in the result?

Each group follows the order of appearance in list A, then in list B for what only exists in B.

Is my data sent to a server?

No: the text you type or paste is processed entirely in your browser, on your device. It is never transmitted to a server.

Do I need to create an account or install anything?

No: the tool works directly in this page, with no sign-up and nothing to install.