Compare text online with side-by-side diff

A text compare tool shows you exactly where two versions of a document diverge. Instead of reading both copies line by line, you paste them side by side and let a diff engine highlight additions, deletions, and unchanged passages in different colours.

Writers use text to text comparison when revising contracts or policy drafts. Developers compare config files, README sections, and API response samples. Support teams check whether a customer pasted the right paragraph from a knowledge-base article. The workflow is the same: original on the left, revised on the right, differences in the panel below.

This page is a free text comparator that works on plain text of any kind — prose, markdown, CSV rows, JSON strings, HTML fragments, or mixed content. No sign-up, no upload queue, and no server-side storage.

To compare text online here, paste your baseline into the Original Text panel and the candidate version into Compare Text. The diff updates as you type, so you can tweak a single word and watch the highlight move immediately.

Import .txt, .md, .csv, or other plain-text files when your source lives on disk rather than the clipboard. Line numbers appear in a gutter beside each editor; changed lines are marked in the gutter so you spot edits before scrolling the full diff table.

Switch between Lines and Words mode depending on what you need. Line mode is ideal for code, legal clauses, and multi-paragraph documents where each row should be treated as a unit. Word mode highlights inline edits inside a sentence — useful when only a few tokens changed between two nearly identical paragraphs.

The Diff Visualizer footer shows how many differences were found, plus line counts for each side. Copy the unified diff or save it as a .txt file to attach to tickets, pull requests, or email threads.

Red backgrounds and strikethrough mean content exists only in the original — a removed line or deleted phrase. Green backgrounds mark additions that appear only in the compare panel. Neutral rows are identical on both sides.

The diff table includes two line-number columns. The left column tracks positions in the original; the right column tracks positions in the revised text. When a line was added, the left column is blank; when a line was removed, the right column is blank. This mirrors how professional diff online checker tools present patches.

A difference count at the top tells you how many changed lines (or word segments, in word mode) were detected. Zero diffs with both panels filled means the texts are byte-for-byte identical — handy before you approve a merge or send a final contract.

Line diff treats each newline as a boundary. Two paragraphs that differ by one character on separate lines show as two changed lines, which is what you want when reviewing git-style patches or numbered legal clauses.

Word diff walks character by character inside each block. If a colleague changed "colour" to "color" mid-sentence, word mode surfaces only that token instead of flagging the entire line. Use it for prose, marketing copy, and short messages where inline edits matter more than row structure.

Neither mode understands programming language syntax — for structured JSON, use our JSON Compare tool, which parses trees before diffing. For arbitrary plain text, this text diff online page is the right starting point.

Legal and editorial teams often receive two Word exports of the same agreement. Copy each version, paste here, and check text difference before signing. Pair with Find and Replace when you need to apply a terminology swap after confirming the diff scope.

Engineers paste environment files, nginx configs, or shell scripts to see what changed between staging and production. Line numbers make it easy to reference "line 42" in a stand-up without opening an IDE.

If your source is a PDF, extract text first with our PDF to Text tool, then compare the exports here. PDF comparison at the layout level needs dedicated software; text-level pdf comparison after extraction is fast and works well for contracts and research papers where formatting is secondary to wording.

Remove All Whitespace can normalize pasted content when line breaks from Word or Excel create false diffs. Run cleanup on both sides, then compare again for a fair text difference checker result.

All comparison runs locally with the diff library in your browser session. Drafts, credentials, and customer data never leave your machine — safe for regulated industries that cannot route content through third-party diffchecker online services.

Very large files may slow the tab; split multi-megabyte logs into sections if scrolling feels sluggish. There is no hard character cap beyond your device memory.

For JSON-specific structural comparison, open JSON Compare. For pattern-based bulk edits after reviewing a diff, use Find and Replace. For counting words in the longer version, try Word Counter. Each tool stays client-side and requires no account.