Text Diff Checker
Compare two texts and highlight what changed, like a git diff. Free to use, no signup required for occasional use.
What is the Text Diff Checker?
The Text Diff Checker is a free online tool that compares two blocks of text and highlights exactly what has changed between them — additions, deletions, and modifications — similar to how a 'diff' view works in version control systems like Git. It's designed for anyone who needs to quickly spot differences between two versions of a document, contract, code snippet, article draft, or configuration file without manually reading through both line by line. Common users include writers comparing draft revisions from an editor, developers reviewing text-based config changes, students checking their work against a reference answer, translators verifying edits, and legal or business professionals comparing contract versions. Manually spotting small wording changes, deleted sentences, or reordered paragraphs across long documents is slow and error-prone; this tool automates that comparison using a diffing algorithm that aligns matching portions of both texts and clearly marks what was added (typically shown in green), what was removed (typically shown in red or strikethrough), and what was left unchanged. The visual highlighting makes it immediately obvious where the two versions diverge, even in long, dense paragraphs where a difference might otherwise be easy to miss. This is especially useful before finalizing a document, verifying that only intended changes were made, or auditing edits made by a collaborator or an AI-based rewriting tool.
How to use it
To compare two pieces of text, paste your original or 'before' text into the first textarea, and paste the updated or 'after' text into the second textarea. Once both boxes contain text, click the 'Compare' button to run the diff. The tool will process both inputs and display a combined, highlighted view showing which words or phrases were removed from the original, which were added in the new version, and which parts remained identical in both. Removed text is typically shown with strikethrough or a red highlight, while added text is shown with a green highlight, making the changes easy to scan visually. This is particularly useful for reviewing edits made by an editor, checking what changed after running text through a paraphrasing or grammar tool, or confirming that a contract revision only touched the clauses you expected. If you need to compare a new set of texts, simply replace the content in either textarea and click 'Compare' again — there is no need to reload the page. For best results with long documents, ensure both texts are pasted in full and retain their original line breaks, since paragraph structure affects how the diff aligns matching sections.
Frequently asked questions
How does the text diff checker decide what counts as a change?
The tool aligns both texts and identifies matching and non-matching segments, marking anything added in the new text or missing from the original as a change.
Can I use this to compare code or only plain text?
It works on any plain text, including code snippets, though it is optimized for prose and general text comparison rather than syntax-aware code diffing.
Is there a limit to how long the compared texts can be?
You can compare fairly long documents, though very large texts may take slightly longer to render the highlighted differences.
Does the diff checker save or store my documents?
No, your text is processed to generate the comparison and is not stored or shared beyond your current session.