Free Text Difference Checker
Compare original and changed text at word or line level, highlight real additions and deletions, and keep both inputs private in your browser.
Browser-local text utility
Runs in your browserCompare two texts
Both editors stay local and remain editable.
Editable plain text · up to 200,000 characters · text is never included in a share URL
0 words0 characters0 lines0 paragraphs
Runs in your browser. The operation is deterministic except an unseeded line shuffle. No source text, result text, seed, search term or comparison content is sent to ScholarTool services.
Current result
Text Difference Checker results
Every visible metric and finding below comes from the current inputs and result.
Complete an operation to begin
The dashboard will show only real output and observed changes.
Detailed findings
Use this result
Result utilities
Exports use the current editable result or comparison.
What is text comparison and what does this Text Difference Checker do?
A text diff computes the insertions and deletions needed to transform one sequence into another. This checker uses the maintained jsdiff implementation for word and line tokenization, then renders both inline changes and paired line rows from the actual inputs.
How to use Text Difference Checker
Paste the original text on the left and changed text on the right.
Choose Word Level or Line Level comparison.
Compare and review additions, deletions, unchanged units and changed lines.
Switch views, swap inputs, edit either version or export the current factual summary.
Key features
- Proven Myers-family jsdiff comparison
- Word-level and line-level modes
- Inline and side-by-side visualizations
- Real additions, deletions, unchanged units and affected-line counts
- Swap, copy, TXT and JSON result utilities
Input guide
Each input supports up to 2,000 words. Word mode treats words and punctuation as comparison tokens while preserving whitespace for display. Line mode treats complete lines as tokens and normalizes CR when comparing Windows and Unix line endings.
How to understand your results
Additions and Deletions count non-whitespace units in word mode or lines in line mode. Unchanged is the retained comparison-unit count. Changed Lines counts added and removed line tokens from a separate line comparison; no similarity or writing-quality score is invented.
Worked example
Example input
Original: The quick brown fox jumps over the dog. Changed: The quick red fox jumped over the sleeping dog.
How to read it
Word mode highlights brown and jumps as deletions, red and jumped as additions, and sleeping as an addition while preserving the shared words.
Common use cases
- Review revisions to an article or policy
- Compare generated and edited copy
- Inspect configuration or list changes by line
- Create a concise change summary for collaborators
Text Difference Checker guidance and best practices
- Use word mode for prose and line mode for records or structured text.
- Treat moved passages as deletion plus addition because a diff does not infer author intent.
- Review the source texts when whitespace or punctuation carries meaning.
Limitations, assumptions and cautions
- The comparison identifies sequence edits, not why they were made.
- Large completely different inputs require more work than similar revisions.
- Formatting outside plain text and document metadata are not compared.
Privacy and processing
Runs in your browser.
Both texts and every diff computation stay in the browser. Sharing and citations contain only the canonical page URL.
Continue this workflow
Related tools
These live canonical tools support a practical next step without duplicating this task.
Find & Replace TextPreview and replace literal words or phrases with explicit first/all, case-sensitive and Unicode whole-word controls.Text CleanerRemove selected whitespace and formatting noise with independent cleanup options, editable output and a factual operation report.Word CounterCount words, characters, sentences and paragraphs while reviewing reading time and useful word-frequency context.
Helpful answers
Text Difference Checker FAQs
Clear guidance for choosing and using the catalogue responsibly.
What does the Text Difference Checker compare?
It compares the actual plain-text sequences in the Original and Changed editors.
What is a word-level diff?
It tokenizes prose into words and punctuation and reports the insertions, deletions and retained segments.
What is a line-level diff?
It treats each complete line as a comparison unit, which is useful for lists, records and configuration text.
What do additions and deletions mean?
An addition exists only in the changed text at that position; a deletion exists only in the original text.
Can I compare large blocks of text?
Yes. Both editors are validated for up to 2,000 words, with performance depending on how different the versions are.
Can I swap the original and changed versions?
Yes. Swap Inputs reverses their roles and recalculates the diff.
Does the tool calculate a similarity score?
No. It focuses on observable additions, deletions, unchanged units and affected lines rather than an arbitrary score.
Does my text remain in my browser?
Yes. jsdiff is bundled into the page and no comparison content is sent elsewhere.