Text Difference
Compare two texts for differences.
Input Information
Result
Compare differences between two texts line by line and highlight them!
The text comparison tool accurately compares differences between two texts line by line, intuitively showing additions, deletions, and changes with colors.
It is useful for quickly checking source code changes during code reviews, reviewing document modifications in contracts and proposals, and finding translation errors by comparing originals with translations.
Statistics for added lines, deleted lines, and identical lines are provided together, making it useful for developers, translators, document managers, students, and anyone who needs text comparison.
Glossary
- diff (Difference Comparison)
- The process of finding and showing additions, deletions, and changes between two texts.
- Line-by-line Comparison
- A comparison method that divides text into lines and judges whether each line is identical, added, or deleted.
- LCS (Longest Common Subsequence)
- An algorithm that finds the longest common subsequence while maintaining order in two strings, used for precise difference comparison.
- 1
Enter original text
Paste the baseline text into the left area.
- 2
Enter comparison text
Paste the modified text into the right area.
- 3
Click compare
Differences appear color-coded: green=added, red=removed, gray=unchanged.
- 4
Review results
Review each changed block for added and removed content.
Example 1 — Translation revision
Original: 'The quick brown fox jumps over the lazy dog' vs revised: '...jumped...' → Only 'jumps→jumped' is highlighted red. Quick way to spot subtle tense changes.
Example 2 — Code review
Paste two code versions side by side: added lines (green) and removed lines (red) are instantly visible — similar to Git diff, directly in the browser.
Text Comparison Algorithm
Each line is compared sequentially to determine if they are identical. When the number of lines differs, the longer text is used as the reference to detect missing parts.
for (let i = 0; i < maxLines; i++) {'{'} if (line1 === line2) → Identical (no change) else → Change detected (addition or deletion){'}'}
Results are categorized as added (green), deleted (red with strikethrough), and identical (no change), and you can see the count of added/deleted/identical lines at a glance in the statistics cards.
Text Comparison Usage Tips
- Code review: Useful for quickly checking source code change history in Git commits or Pull Requests.
- Document comparison: Systematically manage document modifications in contracts, proposals, and papers across versions.
- Translation review: Quickly discover unintentional translation omissions or errors by comparing originals with translations side by side.
- History management: Understand text differences across versions at a glance for systematic change management.
- Email/Official document review: Compare emails or official documents before and after edits to quickly verify changes.
QWhat algorithm does this tool use?
It uses the Longest Common Subsequence (LCS) algorithm, finding the longest common character sequence and marking additions (green) and deletions (red). Both line-level and character-level diffs are supported.
QCan it compare long texts?
Very long texts (tens of thousands of lines) may slow or freeze the browser due to memory limits. For typical document/translation comparisons (hundreds to thousands of lines), it works fine.
QIs the comparison case-sensitive?
By default it is case-sensitive — 'Hello' and 'hello' are treated as different. Convert both to lowercase before input for case-insensitive comparison.
QAre whitespace and line breaks compared too?
All characters including spaces, tabs, and line breaks are compared. 'Hello World' vs 'Hello World' (double space) shows a difference. Trim or normalize whitespace before comparing code.
QCan I share the comparison result?
The tool runs entirely client-side with no server storage. Share results via screenshot or browser print-to-PDF.