Text Difference Checker
Find every change between two texts in seconds. Additions, deletions, and modifications are highlighted clearly — all processed privately in your browser.
This page is part of the main Compare Text tool — the same engine, the same options.
No comparison yet. Paste or upload text in both fields below — results appear here automatically, and nothing is calculated until you do.
Compare your two texts
Original Text (A)0 words
Modified Text (B)0 words
What Is a Text Difference Checker?
A text difference checker (also called a "diff tool") analyzes two pieces of text and pinpoints exactly what changed. It uses algorithms to identify the minimum set of edits — insertions, deletions, and modifications — that transform the original into the modified version.
SnapTextCompare uses Google's diff-match-patch algorithm for word-level and line-level comparison, enhanced with character-level highlighting so you can see exactly which letters changed within a word. It also calculates a Levenshtein-based similarity score to give you an overall measure of how different the two texts are.
This makes it ideal for catching subtle edits that are easy to miss when reading manually — whether it's a single changed word in a legal contract, a modified variable name in code, or a reworded sentence in an essay.
Who Uses a Text Difference Checker?
Writers and editors: Track changes between drafts without relying on Word's "Track Changes" feature. See exactly what was rewritten, added, or deleted across revisions.
Developers: Compare code snippets, config files, or API responses to catch regressions. Works like a lightweight Git diff — directly in your browser.
Legal professionals: Verify contract amendments and ensure no unauthorized edits slipped through. Word-by-word precision catches even minor changes that could affect legal meaning.
Students and researchers: Compare essay versions or check if feedback was properly incorporated. Track how your writing evolved across drafts.
Content teams: Compare marketing copy, email drafts, or product descriptions before publishing. Ensure approved changes are accurate.
How to Check Text Differences
Step 1: Paste the original text in the left panel (or upload a TXT, PDF, or DOCX file).
Step 2: Paste the modified text in the right panel.
Step 3: Differences appear instantly — additions in green, removals in red.
Step 4: Switch between word and line comparison modes. Toggle case sensitivity, ignore whitespace, or switch to unified diff view.
Step 5: Export results or copy the highlighted diff to share with your team.
Related comparison tools
How SnapTextCompare works
Diff engine
Google's diff-match-patch (Apache 2.0), running in your browser. Character mode diffs raw characters; word and line modes encode tokens or lines first and diff those, then decode the result.
Similarity & importance
Similarity = 1 − Levenshtein / max(len). Importance weighs each change by category — money and dates score 90+, punctuation scores 3. Deterministic on any device.
Privacy
Files are read with the HTML5 File API and processed in your browser. No network request is ever made with your content — verifiable in the Network tab of your browser's DevTools.
PDF extraction uses pdf.js (Mozilla). Word extraction uses mammoth.js. UTF-8 with or without BOM is auto-detected; CRLF line endings are normalised to LF before diffing so cross-OS files don't appear entirely changed.
Related Guides
The Ultimate Guide to Comparing Text
Everything about text comparison — tools, methods, and real use cases.
Word vs Line Comparison
Understanding comparison modes for clearer results every time.
How to Compare Text Without Coding
A beginner-friendly guide to comparing text online.
Find Differences Between Two Documents
Quick guide to finding differences between any two documents.
Text Difference Checker FAQ
Common questions about checking text differences.