Text Diff Tool - Find Changes | Document Comparison

Compare two texts and highlight added/deleted parts in green/red. Perfect for document comparison, code review, and contract change verification.

How to Use

Quickly compare two texts and identify differences

  • 1. Enter the original text in "Text A"
  • 2. Enter the modified text in "Text B"
  • 3. Added/deleted characters are highlighted in green/red in real-time

About Text Comparison

A tool that finds and visually displays differences between two texts. Compares character by character, showing additions in green and deletions in red.

Use Cases

Document before/after comparison, contract change verification, code review, email draft comparison, translation comparison, report revision checking, and more.

※ Notice

  • Compares character by character (each character is compared individually).
  • Red text + light red background: Deleted characters (with strikethrough).
  • Green text + light green background: Added characters (in bold).
  • Whitespace and line breaks are included in comparison.
  • Case-sensitive comparison.

Frequently Asked Questions

How does text comparison work?

This tool compares two texts character by character and displays added or deleted parts in color. Green indicates newly added characters, and red with strikethrough indicates deleted characters. Comparison results update in real-time as you type.

What is the difference between line-by-line and word-by-word comparison?

Line-by-line comparison treats each entire line as one unit and shows changed lines as a whole. Word-by-word comparison identifies changes at the individual word level. This tool uses more granular character-by-character comparison to pinpoint exact change locations.

Can it be used for code comparison?

Yes, it can be used for programming code comparison too. Paste two versions of code to immediately see which parts were modified. However, for professional code reviews, it is recommended to also use Git diff or the comparison feature in a dedicated IDE.

How do I interpret the comparison results?

In the comparison results, bold green text indicates content added in Text B, and red strikethrough text indicates content deleted from Text A. Parts with no color change are identical in both texts. The message "Both texts are identical" means there are no differences.

Diverse Uses of Text Comparison Tools

Document Editing and Contract Review

Text comparison tools are a great help when quickly contrasting the before and after versions of a document. You can instantly see whether contract clauses have changed or which sentences were added or removed in a report. In legal, financial, and compliance fields, accurately tracking document change history is critical, making text diff tools an essential utility.

How the Diff Algorithm Works

The diff algorithm calculates the Minimum Edit Distance between two text sequences. The well-known LCS (Longest Common Subsequence) algorithm finds the longest common subsequence shared by both texts, then marks the remaining parts as insertions or deletions. Git's diff feature, code review tools, and word processor track-changes functionality are all based on this principle.

Translation Quality Review and Proofreading

Text comparison tools greatly improve efficiency when comparing a translated document against the original or contrasting pre- and post-proofread text. Even when only a small portion of a document hundreds of pages long has been modified, the changed sections can be identified instantly, saving significant time.

This calculator is provided for informational purposes only.

Results are estimates and may differ from actual amounts.

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