Text Differ: Compare Text and Find Differences

Compare two versions of text and instantly see what changed. Side-by-side diff with color-coded additions, deletions, and modifications. Perfect for code reviews, document versioning, and plagiarism detection.

Ignore whitespace

Ignore case

Original Text

Modified Text

Text Diff Comparison

This tool compares two texts and highlights the differences line by line. Green indicates added lines, red indicates removed lines.

Side-by-side view for detailed comparison
Inline view for quick overview
Option to ignore whitespace differences
Option to ignore case differences

How It Works

This tool compares two versions of text line by line using the Longest Common Subsequence (LCS) algorithm. It identifies which lines appear in both versions, which lines were added in the modified text, and which lines were removed from the original.

The diff engine splits both inputs by newline characters, then computes the optimal alignment between them. Lines that match exactly are marked as unchanged. Lines only in the original are marked as removed (shown in red). Lines only in the modified version are marked as added (shown in green).

Diff view options:

Side-by-side: Original on the left, modified on the right. Best for detailed line-by-line comparison with line numbers visible.

Inline: Both versions in a single column with + and - prefixes. Compact view similar to git diff output.

You can enable "Ignore whitespace" to treat multiple spaces as one, or "Ignore case" to make the comparison case-insensitive. These options help when formatting changes aren't relevant to your comparison.

When You'd Actually Use This

Reviewing code changes before committing

A developer finishes a feature and wants to see exactly what changed before committing. They paste the original file content and their modified version to verify they didn't accidentally delete important lines or introduce formatting errors.

Comparing document revisions

A writer receives an edited draft from their editor. Instead of wrestling with Track Changes, they paste both versions into the differ to quickly see what paragraphs were rewritten, added, or removed entirely.

Verifying configuration file updates

An ops team member updates a production config file. Before deploying, they compare the old and new versions to ensure only intended changes were made and no critical settings were accidentally modified or deleted.

Checking plagiarism or content duplication

A teacher suspects a student copied content. They paste the original source and the student's submission to identify matching passages and determine how much was directly copied versus paraphrased.

Merging conflicting edits from teammates

Two developers edited the same configuration file independently. Before merging, one pastes both versions to understand what each person changed, then manually combines the edits without losing either person's work.

Debugging why output changed

A data analyst's report output looks different after a code change. They compare the old and new output files to pinpoint exactly which numbers or formatting changed, helping them trace the bug to its source.

What to Know Before Using

Comparison is line-based, not character-based.The tool highlights entire lines that differ, not individual characters within lines. If you change one word in a 100-character line, the whole line shows as changed. For character-level diffs, use a specialized tool.

Line order affects the diff output.Moving a block of lines from one position to another shows as deletions and additions, not moves. The LCS algorithm finds the longest matching sequence, so large reorganizations may show more changes than expected.

Whitespace ignoring affects all comparisons.When "Ignore whitespace" is enabled, tabs vs spaces don't matter, and multiple spaces equal one space. This is useful for formatting changes but can hide meaningful whitespace differences in code.

Empty lines are significant.Adding or removing blank lines shows as changes. This is usually correct for code (where blank lines affect readability) but can clutter diffs for plain text where blank lines are decorative.

Pro tip: For code reviews, use side-by-side view with line numbers to reference specific changes. For quick "what changed" checks, inline view is faster. The stats counter helps you gauge the scope of changes at a glance.

Common Questions

How is this different from git diff?

Git diff works on files in a repository and shows character-level changes within lines. This tool works on any pasted text without needing version control. It's line-based and better for quick comparisons outside of git workflows.

Can I compare more than two versions?

No, this tool compares exactly two texts. For three-way merges or comparing multiple versions, use git's three-way merge tool or specialized diff software like Beyond Compare or KDiff3.

What happens with very large files?

The LCS algorithm has O(m*n) complexity, so comparing files with thousands of lines each may be slow. For large codebases, use command-line diff tools or IDE built-in comparison features optimized for performance.

Does it support binary file comparison?

No, this tool is designed for text only. Binary files (images, executables, etc.) need hex-based comparison tools. For binary diffs, use specialized tools like diffoscope or binary comparison utilities.

Can I export or save the diff results?

The diff is displayed in your browser but isn't directly exportable. You can screenshot the results or copy the highlighted output. For permanent records, consider using command-line diff with output redirection.

Why do some lines show as changed when they look identical?

Hidden characters like trailing spaces, tabs vs spaces, or different line endings (CRLF vs LF) can cause apparent matches to show as different. Enable "Ignore whitespace" to filter out these formatting differences.

Is my data sent to a server?

No, all comparison happens locally in your browser. Your text never leaves your computer. This makes the tool safe for comparing sensitive code, confidential documents, or proprietary configurations.

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