Diff Checker: Compare Text Online and Find Differences

This free diff checker compares two versions of a text and shows exactly what changed. Paste the original on the left and the new version on the right: removed lines turn red, added lines turn green, and the changed words inside each line are highlighted. Use it to compare text from contracts, essays, code, configuration files or two copies of a web page.

Original text

Changed text

Ignore upper and lower case Ignore extra spaces

Everything runs in your browser. Your text is never sent to or stored on our server.

Quick answer: Paste the old text in the left box and the new text in the right box, then click Find differences. Lines marked – in red were removed, lines marked + in green were added, and highlighted words show what changed inside a line.

How to compare two texts

Paste the original version into Original text.
Paste the edited version into Changed text.
Tick Ignore upper and lower case or Ignore extra spaces if those changes don’t matter to you.
Click Find differences. The counters show how many lines were removed, added and left unchanged.

How to read the results

White lines are the same in both versions. The two numbers on the left are the line numbers in each text.
Red lines with a minus sign exist only in the original.
Green lines with a plus sign exist only in the changed text.
When a line was edited rather than replaced, it appears once in red and once in green, with the exact words that changed highlighted, so you don’t have to hunt for a single altered word.

The checker finds the longest run of lines the two texts share, the same approach used by the classic diff command and by Git, so moved blocks show up as removed in one place and added in another.

What people use a diff checker for

Documents and contracts: see what the other side changed in a returned draft.
Writing and editing: compare your draft with an edited version, or check what an AI rewrite actually changed.
Code and settings: spot the one changed line in a config file, .htaccess or CSS before you upload it.
SEO and web pages: compare two versions of a page’s text, title tags or robots.txt.
Lists: find which items were added to or removed from a list. Sorting both lists first with our alphabetical order tool makes the differences clearer.

Compare documents in Word and Google Docs

For formatted documents, the built-in tools keep formatting and tracked changes:

Microsoft Word: Review > Compare > Compare, then pick the original and revised documents.
Google Docs: open one document and choose Tools > Compare documents.

Use this diff checker when the text comes from anywhere else, or when you just want a fast, plain-text comparison without uploading files.

FAQ

Is the text I compare kept private?

Yes. The comparison runs in your browser. Nothing you paste is uploaded or saved, so it is safe for contracts, passwords in config files or unpublished writing.

How long can the texts be?

Up to about 2,400 lines on each side. For longer files, compare them in sections.

Why is a moved paragraph shown as removed and added?

A line-by-line diff can only match lines in the same order. If you move a paragraph, it appears as removed from its old position and added in its new one.