Text Compare Online: Compare Two Texts
Paste or open two text files and find every changed line, word, and character.
Comparison content is processed in this browser and is not uploaded to DiffPeek.
Free online text comparison tool
Use this text compare tool to compare two texts side by side or switch to a unified diff. DiffPeek highlights added, removed, and modified lines, then marks the exact words and characters that changed. It works with plain text, notes, articles, documentation, configuration, and other text-based content.
Choose Smart highlighting for readable replacements, Word for token-level review, or Char for exact inline detail. Use ignore-case and ignore-whitespace options for noisy edits, collapse unchanged context, and jump between changes. Search the complete result or go directly to a line even when a large comparison is only partly mounted on screen. Select a changed row to edit either side or merge that one change left-to-right or right-to-left, then undo, redo, copy, or download the result. Processing happens locally in your browser.
How to compare two text files online
- Paste the original text on the left and the revised text on the right, or open a local file in each pane.
- Choose the matching options you need, then click Compare to build the text diff.
- Read green additions and red deletions in the side-by-side view, or switch to Unified for a single review stream.
- Select one changed row to copy it, edit it, or merge that change into the other side. Nothing is merged automatically.
- Download the edited result or export a standard
.diffpatch when the review is complete.
What the comparison colors mean
Green marks content present only in the changed text. Red marks content present only in the original text. A modified line can contain both colors because the comparison pairs a deletion with its closest addition. Unchanged lines stay neutral. These counts describe the current comparison; after a merge or edit, DiffPeek recalculates them from the browser-side copies.
Try the edit → merge → undo workflow
Open the release-notes example, select a changed row, edit either browser-side copy, and use the mirrored merge control for that change. Undo restores the prior browser state; Download result saves the selected side and Download .diff exports a UTF-8 LF unified patch.
Ignore options affect matching and review only. They do not rewrite capitalization or whitespace in the downloaded result.
Text comparison limits
Each side accepts up to 10 MiB of JavaScript text and 100,000 lines. The UI renders a bounded result window for large comparisons, skips character highlighting on paired lines above 20,000 characters, and clearly labels reduced-precision line grouping when the exact trace-work limit is reached.
Private by design
Your text documents stay in the active browser tab while you compare them. DiffPeek does not upload comparison content to an account or remote comparison service. Closing or refreshing the page clears the working comparison unless you first download the result. This makes the tool useful for drafts and source snippets, but you should still follow your organization’s rules for sensitive information.
Comparing source files instead? Try Code Compare, open two local files with the File Diff Checker, or scan a whole project with the Folder Diff Checker.