About the Text Diff / Difference Checker
Comparing two versions of a document by eye is slow and error-prone, especially for longer text where a single changed word can be easy to miss. This Text Diff Checker highlights exactly what changed between two blocks of text — additions in green, deletions in red — so you can review edits in seconds rather than minutes.
This tool is useful for writers and editors comparing draft revisions, translators checking a translated text against updates to the source, and students or teachers comparing submitted work against a reference or previous version.
To use it, paste your original text into the left box and your revised text into the right box, then click Compare. Every difference is highlighted inline — added text appears in green, removed text appears struck through in red — letting you scan the full document while only really needing to focus on the highlighted changes. Switch between word-level (best for prose) and line-level (best for structured lists or code-like text) comparison modes depending on your content.
For example, comparing two paragraphs of website copy where only a call-to-action sentence changed will show that single sentence highlighted, while every other unchanged sentence remains in plain text — instantly confirming that no accidental changes were introduced elsewhere in the document during editing.
A common mistake is comparing text copied from different sources (like a Word document versus a plain text file) without realizing they may contain invisible differences like curly vs. straight quotes or different line-ending characters, which can show up as unexpected "changes" even when the visible content looks identical — if you see unusual highlighted differences in seemingly identical text, check for these hidden formatting artifacts. Another good practice is doing a final diff check immediately before publishing any heavily-edited document, since it's the most reliable way to catch an accidental deletion or unintended change introduced during a late editing pass.
Tip: for reviewing legal contracts, terms of service updates, or policy documents, always do a full diff comparison between versions rather than relying on a summary of changes provided by someone else, since a diff tool catches every single alteration objectively, including ones that might otherwise be easy to overlook or unintentionally omitted from a manual summary.