Text Diff Checker
Compare two texts side by side. Additions, deletions, and unchanged lines are color-coded for easy identification.
About Text Diff Checker
Comparing two versions of text — to find what changed between drafts, what differs between configuration files, or what edits a collaborator made — is something most of us do in the dark by skimming back and forth. This text diff tool puts both versions side by side with additions, deletions, and unchanged lines visually distinguished, so you can see every change in a single pass.
Useful for reviewing edits on contracts, comparing configuration files between environments, spotting accidental changes in copy-paste workflows, and providing structured feedback on drafts. The diff happens locally, which matters when the content is confidential — legal documents, sensitive emails, internal proposals — and you cannot upload it to an online comparison tool.
How to Use
Paste the original text in the left box and the modified text in the right box.
Differences are highlighted automatically: green for additions, red for deletions.
Use the options to ignore case or trim whitespace for more flexible comparison.
Check the stats bar to see the count of additions, deletions, and unchanged lines.
Frequently Asked Questions
How does the diff algorithm work?
This tool uses a Longest Common Subsequence (LCS) algorithm to compare lines. It finds the best alignment between the two texts and highlights additions and deletions.
Can I compare large texts?
Yes, but very large texts (thousands of lines) may take a moment to process. The algorithm runs entirely in your browser.
What do the colors mean?
Green lines are additions (present in the new text but not the original). Red lines are deletions (present in the original but not the new text). White/default lines are unchanged.
Text Diff Checker Online: Compare Two Texts Side by Side
Spotting changes between two text versions by eye is slow and error-prone. A diff checker shows exactly what was added, removed, and unchanged in seconds.
Read the full guide