Compare two texts and instantly see what's added, removed, or changed. Line-by-line or word-by-word comparison. Perfect for code review, contract comparison, and document changes. 100% private — runs in your browser.
Original Text 0 chars
Changed Text 0 chars
0Added
0Removed
0Unchanged
0%Similarity
Comparison ResultLINE DIFF
How to Use This Tool
1
Paste both texts
Original on the left, changed version on the right. Works with code, prose, or any plain text.
2
Choose diff mode
Line Diff for code and structured text. Word Diff to spot small edits within sentences.
3
Click Compare
Green = added, Red = removed. Stats show exact counts and similarity percentage.
4
Review differences
Scroll through the highlighted output. Use Swap to reverse direction, or Clear to start fresh.
Comparing two versions of text manually is error-prone and slow — the human eye easily misses small changes buried in long paragraphs or code files. A diff checker automates this by computing exactly what changed and highlighting it visually.
Use Case
Best Mode
Example
Code review
Line Diff
Compare two versions of a function or config file
Contract / legal review
Word Diff
Spot a single changed clause or number in a long document
Translation QA
Word Diff
Compare original vs edited translation for accuracy
Resume/document versions
Line Diff
See exactly what changed between draft versions
Plagiarism spot-check
Word Diff
Compare two essays for overlapping phrasing
Line Diff vs Word Diff — When to Use Each
Line diff treats each line as a unit. If even one character changes within a line, the entire line is marked as removed (old version) and added (new version). This is ideal for code, where line boundaries matter and you want a git-diff-style view.
Word diff breaks text into words and finds exactly which words were added or removed, even within the same line. This is far more precise for prose — a single-word edit in a 50-word sentence shows just that word highlighted, not the entire sentence.
💡For comparing source code, always use Line Diff — it matches the format developers expect from version control tools. For comparing essays, contracts, or any prose, use Word Diff for precision.
How the Diff Algorithm Works
This tool uses a Longest Common Subsequence (LCS) based algorithm — the same family of algorithms used by Git, diff utilities on Linux, and most version control systems. The algorithm finds the longest sequence of lines or words that appear in the same order in both texts (the "unchanged" portion), then marks everything else as added or removed.
This approach minimizes the number of changes shown — rather than naively comparing position-by-position (which would mark almost everything as different if even one line was inserted near the top), it intelligently aligns matching content and isolates only the genuine differences.
Frequently Asked Questions
A text diff checker compares two pieces of text and highlights differences. Common uses: code review, contract review, comparing document drafts, translation quality checks, and verifying configuration changes. It saves significant time versus manually reading both texts side by side.
Line diff compares texts line by line — useful for code where entire lines change. Word diff compares word by word within lines — useful for spotting small edits like a single changed word in a sentence, which line diff would mark as the entire line different.
Yes. This diff checker runs entirely in your browser using JavaScript. Neither text is uploaded to any server, logged, or stored. It's safe to compare confidential contracts, proprietary source code, or any sensitive document — nothing leaves your device.
This tool uses a Longest Common Subsequence (LCS) based algorithm, the same family used by Git and Unix diff. It finds the longest matching sequence of lines/words present in both texts, then marks everything outside that sequence as added or removed — minimizing the reported changes.
Yes. Paste old code on the left, new code on the right, and use Line Diff mode. It highlights added lines (green), removed lines (red), and unchanged lines — similar to git diff output but without needing Git installed. Works for any programming language since it's plain text comparison.
Git diff compares tracked file versions in a repository using a unified +/- format. This tool provides similar line-level comparison with visual color highlighting, no Git installation required, and also offers word-level diff for prose — which Git diff doesn't show by default.
📅 June 2026 · Written by the ToolLoom Team · Reviewed for accuracy June 2026 About ToolLoom: Diff algorithm uses Longest Common Subsequence (LCS) — the same approach used by Git and Unix diff utilities. All comparison runs locally in your browser. Found an error? Email contact@toolloom.in