Free Text Diff Checker Online
Paste two versions of text below and click Compare. Added lines are highlighted in green, removed lines in red, changed lines in yellow.
About the Text Diff Checker
The Text Diff Checker performs a line-by-line comparison of two text inputs and highlights the differences. It uses a longest-common-subsequence (LCS) algorithm to detect added, removed and unchanged lines. The optional word-level diff further highlights which specific words within changed lines differ.
Use it to compare versions of documents, code snippets, configuration files or any other text to see exactly what changed between revisions.
How to Use the Text Diff Checker
Paste Text A (Original)
Paste your original/old text into the left input box.
Paste Text B (Modified)
Paste the new/modified version of the text into the right input box.
Click Compare
Press "Compare Texts" to see the diff highlighted below.
Read the Results
Green = added, Red = removed, Yellow = changed line. Enable "Word-level diff" to see exactly which words changed.
Frequently Asked Questions
The tool uses a Longest Common Subsequence (LCS) algorithm applied line by line. This is the same algorithm used by the Unix diff command. It identifies the maximum set of lines that appear in both texts in the same order, then marks the rest as added or removed.
Yes. Paste any code, configuration or plain text into the two boxes. The diff works on any text content. For very large files (>50 KB each) performance may be slower due to client-side LCS complexity.
When enabled, leading/trailing whitespace is stripped and consecutive spaces are collapsed before comparison. This means lines that differ only in indentation are treated as the same.
By default yes — "Apple" and "apple" are considered different. Toggle "Ignore case" to make the comparison case-insensitive.