Compare text or documents

Paste the original into the left panel and the changed version into the right. The comparison runs as you type — there is no compare button — and shows the two texts side by side with matching content aligned on the same row. Additions, deletions, edits and moved blocks each get their own marker, and a similarity score above the result tells you how close the two versions are overall.

Drag each file onto a panel, or use the Open file button on it, and the contents load in place — or open the files yourself and paste. Nothing is uploaded: the file is read in your browser, so comparing two files here does not send them anywhere. Any text file works, whatever its extension — .txt and Markdown, source code in any language including .cpp, .c, .h, .java, .py, .go, .rs, .sql and .sh, plus JSON, YAML, CSV and configuration files. Word .docx files and PDFs work too, with their text extracted in the browser as they are dropped. The two files do not need the same name or extension. A scanned PDF is the one case that cannot work, because a scan is an image of text with no text layer to read.

Put one version in each panel and the result is laid out as two aligned columns, so corresponding content sits on the same row and you read the difference across rather than scrolling between two windows. Where a block was relocated, a connector links its old and new position, and inside a line that was edited the specific words that changed are highlighted.

Yes. The tool is completely free, with no sign-up, no account, and no limit on how many comparisons you run. There is no paid tier holding features back.

This one is free with no account or install, and there are other good free options: Diffchecker and Text Compare in the browser, Meld and WinMerge as desktop applications, and "git diff" or the "diff" command if you already work in a terminal. What varies most between them is whether they can recognise relocated content — a plain sequential comparison reports a moved paragraph as a deletion plus an unrelated addition.

Several, and the right one depends on what you need from the answer. Word's built-in Compare feature and Google Docs' version history track changes inside the document itself, keeping the formatting, which is what you want if a restyled heading or a new table column is the thing you are checking. This tool takes the other approach: drop a .docx or a PDF on a panel and its text is extracted in your browser, then compared in paragraph blocks. Formatting is discarded, and what you get in exchange is the whole set of wording changes on one screen, including passages that were relocated rather than rewritten.

There is no single best one; it depends on what you are comparing. For merging code with version-control integration, Beyond Compare, Meld and WinMerge are the established choices. For a quick side-by-side check with nothing to install, a browser tool is quicker. What is worth checking before you trust any of them is how they handle reordered content, since a sequential comparison reports a moved block as two unrelated changes and scores near zero on a document that is fully intact.

File comparison is the process of examining two files to identify exactly where their contents differ. A comparison tool aligns the parts that match and reports the rest as added, deleted or changed, usually with a summary of how similar the two files are. It answers a narrower question than "are these the same?" — it tells you precisely what changed and where, which is what you need to review an edit or track down when something broke.

Text comparison is the process of analyzing two pieces of text side by side to identify exactly where they match and where they differ. Rather than just checking if two texts are identical, a comparison tool aligns corresponding sections and highlights additions, deletions, modified words, and moved blocks so you can easily review changes between drafts, documents, or code.

The same way as any other language: paste both versions and read the aligned result. For natural language the unit of comparison is the paragraph block rather than the single line, so a reworded sentence is reported as one edited paragraph with the changed words highlighted inside it, instead of as a whole rewritten block. It is not English-specific — any language that uses spaces between words behaves the same way.

Put them side by side, line up the parts that correspond, and decide in advance which differences actually matter to you — otherwise every trivial variation competes for attention with the ones that count. For two versions of a text, that is exactly what a diff tool automates: it aligns the matching content for you and marks only what genuinely differs, so you are reading a short list of changes rather than two full documents.

No. Parsing and comparison run in a Web Worker in your browser, and there is no endpoint here to receive your text. The requests the page does make are for the page itself, the language grammar file the first time you compare a given language, Google Analytics, which counts the visit, and Google AdSense, which pays for hosting. None of them is ever given the text you compared, because the text is never sent anywhere at all.

Yes. Switch Case sensitive off and capitalisation differences are ignored, so a recapitalised sentence does not read as a change. It is on by default, because Value and value are genuinely different things in code and in anything where a name has to match exactly. The setting applies to both the Smart and Strict engines.

JavaScript, TypeScript, TSX, Python, JSON, CSS and HTML are parsed into syntax trees. Anything else — Markdown, plain prose, and code in any other language — is compared in blocks separated by blank lines, or line by line when the text has no blank-line separation. That still detects reordering, just without syntax awareness: a relocated block is reported as a move, but a renamed identifier inside it is not recognised as a rename.

Matched content counts in full, edited content counts in proportion to how similar it is, and added or deleted content counts as zero — all weighted by size, so a relocated 50-line function matters more than a moved one-liner. Both engines use that one formula, which is why the same documents can score high in Smart mode and low in Strict: one measure, applied to two different notions of a match.