Compare Two Texts (Diff Checker)
Free online diff checker tool. Compare two versions of code, essays, or text blocks to highlight line additions, deletions, and updates.
Text Compare & Diff Checker
Quickly detect additions, deletions, and subtle character edits between two blocks of text, code, or data files.
Diff Results
| # | Original Content | # | Modified Content |
|---|---|---|---|
| 1 | function calculateTotal(price, taxRate) { | ||
| 2 | // Calculate total with tax | ||
| 3 | var subtotal = price; | ||
| 4 | var tax = subtotal * taxRate; | ||
| 5 | var finalTotal = subtotal + tax; | ||
| 6 | return finalTotal; | 1 | function calculateTotal(price, taxRate, discount = 0) { |
| 2 | // Calculate total with tax and optional discount | ||
| 3 | const discountedPrice = Math.max(0, price - discount); | ||
| 4 | const tax = discountedPrice * taxRate; | ||
| 5 | const finalTotal = discountedPrice + tax; | ||
| 6 | return Number(finalTotal.toFixed(2)); | ||
| 7 | } | 7 | } |
Step-by-Step Instructions
Input Original and Modified Text
Paste your baseline text in the left pane (Original) and the revised version in the right pane (Modified).
Choose Comparison Granularity
Select whether you want to compare changes character-by-character, word-by-word, or line-by-line.
Inspect Visual Diff Highlights
Analyze color-coded visual feedback highlighting added text (green), removed text (red), and unchanged baseline content.
Export or Copy Diff Summary
Review similarity percentage, total edits, and copy the unified diff or side-by-side comparison report.
Key Features & Capabilities
- Advanced Myers diff algorithm computing the Longest Common Subsequence (LCS) for mathematically optimal change detection
- Multi-level comparison modes: Character-by-character, word-by-word, and line-by-line diffing
- Side-by-side split screen view and unified inline change view with synchronized scrolling
- Real-time change metrics: calculates exact similarity percentage, insertions count, and deletions count
- Whitespace and case-sensitivity toggles to ignore trivial formatting differences
- 100% private in-browser comparison: proprietary legal contracts, code, and confidential essays are never uploaded
Frequently Asked Questions
What diff algorithm is used to compare text differences?
The text comparison engine implements Eugene Myers' difference algorithm, finding the Longest Common Subsequence (LCS) between two text sequences with `O((N+M)D)` time and space complexity, identical to the core engine used in GNU diff and Git.
What is the difference between word-level diff and line-level diff?
Line diffing highlights entire lines that have been added or removed, which is standard for code reviews. Word diffing highlights exact words changed within sentences, making it far easier to proofread essays, editorial revisions, and legal contracts.
Can I ignore whitespace changes and casing differences?
Yes. You can toggle flags to ignore leading/trailing whitespace, collapse multiple spaces, or make comparisons case-insensitive to focus only on substantive content edits.
Are my confidential legal contracts or code files safe?
Yes. The diff comparison runs entirely on your local CPU inside your browser runtime. Zero text or file data is ever transmitted over the network.
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