Our Simple Diff Checker is a free online tool that lets you compare two blocks of text side by side and instantly see the differences. Whether you are comparing two versions of a document, checking code changes, or reviewing edited content, this tool highlights exactly what was added, removed, or modified.

Simply paste or type your original text in the left column and the modified text in the right column, then click the "Compare" button. The tool runs a line-by-line comparison and presents the results in a clear, color-coded table. You can also upload plain text files directly into each column.

Side-by-Side Comparison: Both texts are displayed next to each other in a clear two-column layout, making it easy to see what changed and where.

Color-Coded Differences: Added lines are shown in green, deleted lines in red, and modified lines in yellow. Unchanged lines appear in white.

Line Numbers: Each line is numbered so you can quickly identify exactly which lines differ between the two texts.

Ignore Whitespace: Enable this option to ignore leading and trailing whitespace differences. Useful when comparing text that has inconsistent indentation.

Case-Insensitive: Enable this option to treat uppercase and lowercase letters as the same, so only actual content changes are flagged.

File Upload: Upload .txt files directly into the Original or Modified columns instead of pasting text manually.

Copy Diff: Copy the comparison results to your clipboard for sharing or record-keeping.

Change Summary: After comparison, a summary shows the number of lines added, removed, and modified.

Below is a simple example to demonstrate how the tool works:

Project Alpha - Status Report
Deadline: March 15, 2025
Budget: 50000
Team lead: Alice Johnson
Status: On track
Priority: High
Next milestone: Beta launch

Project Alpha - Status Report
Deadline: April 1, 2025
Budget: 55000
Team lead: Alice Johnson
Status: On track
Next milestone: Beta launch
Reviewer: Bob Smith

  Project Alpha - Status Report     Project Alpha - Status Report
  Deadline: March 15, 2025           Deadline: April 1, 2025
  Budget: 50000                       Budget: 55000
  Team lead: Alice Johnson          Team lead: Alice Johnson
  Status: On track                  Status: On track
  Priority: High
  Next milestone: Beta launch       Next milestone: Beta launch
                                      Reviewer: Bob Smith

The tool identifies red lines as deleted from the original, green lines as newly added, and yellow lines as modified (present in both but with different content).

1. Enter your texts: Paste or type your original text in the "Original (Column A)" textarea and the modified version in the "Modified (Column B)" textarea. Alternatively, upload .txt files using the file upload inputs.

2. Configure options (optional): If needed, check "Ignore leading/trailing whitespace" or "Case-insensitive comparison" before comparing.

3. Click Compare: Press the "Compare" button. The tool will display a color-coded side-by-side comparison showing exactly what changed between the two texts.

4. Review results: Green rows indicate lines present only in the modified text. Red rows indicate lines present only in the original. Yellow rows indicate lines that exist in both but have different content.

5. Copy or go back: Use "Copy Diff" to copy the results to your clipboard. Click "Go Back" to edit the texts and compare again, or "Reset" to clear everything.

Comparing Document Versions: When you have two versions of a text document and need to quickly identify what changed between them, this tool gives you a clear visual summary.

Reviewing Edited Content: Writers and editors can compare drafts to see exactly what was added, removed, or rewritten during the editing process.

Checking Code Changes: Developers can compare snippets of code, configuration files, or markup to spot differences before committing changes.

Verifying Data Entries: When comparing two lists or data sets, this tool quickly highlights missing or extra entries.

Educational Use: Students and teachers can use the tool to compare answers, review assignments, or demonstrate text differences in a visual way.

FAQ 1: Does this tool compare text line by line?
Answer: Yes, the Simple Diff Checker compares your texts line by line. Each line in the Original is matched against the corresponding line in the Modified text to find additions, deletions, and modifications.

FAQ 2: What is the difference between red, green, and yellow highlights?
Answer: Green means the line exists only in the Modified text (added). Red means the line exists only in the Original text (deleted). Yellow means both texts have a line at that position but the content is different (modified).

FAQ 3: What does "Ignore leading/trailing whitespace" do?
Answer: When enabled, the tool strips spaces and tabs from the beginning and end of each line before comparing. This prevents minor indentation differences from being flagged as changes.

FAQ 4: Is there a limit on text size?
Answer: There is no strict limit, but very large texts (tens of thousands of lines) may take a moment to process. For best performance, keep texts under a few thousand lines per comparison.

FAQ 5: Can I upload files instead of pasting text?
Answer: Yes, you can upload .txt files using the file upload inputs above each textarea. The file contents will be loaded into the corresponding column.

FAQ 6: Does this tool save my text?
Answer: No, all processing happens entirely in your browser. No text data is sent to any server, so your content remains private.