Text Tools
Text Diff Checker
Compare two text versions by line, word or character. Review changes side by side, as unified text or as a concise summary without uploading either text to ToolHub.
Compare two text versions
Text Diff Checker
Compare inert text locally. Additions and removals carry text labels as well as color.
Preview is limited to 200,000 characters. Copy and Download include the full result.
How this tool works and limits
Bounded Myers shortest-edit-path diff in a worker. Line comparison is always calculated for the summary; Word/Character adds a bounded inline diff. Comparison normalization never changes displayed source strings. Ignore all whitespace ignores token boundaries for inline comparison. Limits: 2 MB per side, 50,000 lines, 20,000 inline tokens, 500,000 frontier/trace entries, 4-second worker timeout. Complex line changes use a documented block replacement fallback; inline overload falls back to line output. Unified output is human-readable text, not a guaranteed Git patch. Line-ending markers are omitted from the table but preserved in inputs.
Your input is processed locally in your browser and is not uploaded or stored by this tool.
Comparison runs locally in a dedicated worker. The tool treats both inputs as inert text and does not upload them to the ToolHub server.
How to use the text diff checker
- 1
Paste or load the original text and the changed version.
- 2
Choose Line, Word or Character diff mode.
- 3
Select Side-by-Side, Unified or Summary output.
- 4
Optionally ignore case, trim outer whitespace, ignore all whitespace or normalize line endings.
- 5
Run the comparison and review additions, removals, changed pairs and unchanged lines.
Text comparison example
Suppose the original contains “Status: draft”, “Owner: Ana” and “Due: Friday”. The revised version changes the status to approved, changes Friday to Monday and adds “Reviewer: Kai”. The summary identifies two changed line pairs, one added line and one unchanged line.
Side-by-side view keeps both line numbers visible. Unified view marks removals with minus signs and additions with plus signs for a compact, copyable report.
Line, word and character diff modes
Line mode is useful for configuration, lists, drafts and source-like text where line structure matters. Word mode provides a more detailed inline view for prose. Character mode can expose punctuation, spacing or very small edits. Every mode still calculates a line-level result for the summary.
Case and whitespace options
Ignore Case treats uppercase and lowercase forms as equal during comparison. Ignore Leading/Trailing Whitespace trims the outer edges of each compared line. Ignore All Whitespace removes whitespace for matching, which can also remove meaningful token boundaries. Normalize Line Endings treats Windows, macOS and Unix line breaks consistently. These options change comparison keys, not the displayed source strings.
How the diff is produced
The tool uses a bounded Myers shortest-edit-path comparison in a worker. If a large or difficult block exceeds the work limit, it falls back to showing that block as removal and addition instead of claiming a minimal edit path. Word or character overload falls back to the line result.
Important limitations
- Input limits: each side is limited to 2 MB and 50,000 lines.
- Inline limits: word or character comparison is bounded to 20,000 tokens and a 200,000-character preview.
- Human-readable output: Unified view is not guaranteed to be a valid Git patch.
- Meaning: the tool identifies textual changes but cannot judge whether they are factually or legally important.
- Formatting: rich-document layout, comments and tracked-change metadata are not preserved.
Related tools
Text Diff Checker FAQ
What is a text diff checker?
It compares an original text with a changed version and reports additions, removals and matches.
Which diff mode should I choose?
Use line mode for structured text, word mode for prose and character mode for very small edits.
Can the tool ignore capitalization?
Yes. Enable Ignore Case to compare uppercase and lowercase forms as equal.
Does ignoring whitespace change the displayed text?
No. Normalization changes the comparison keys while the source strings remain visible.
Is Unified view a Git patch?
No. It is a human-readable text report and is not guaranteed to apply as a patch.
Are my text files uploaded?
No. Selected TXT files and pasted text are processed locally in your browser.
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