Is the Text Diff Viewer free to use?

Yes, the Text Diff Viewer is completely free. No account, subscription, or signup is required — ever.

Does my data get uploaded anywhere?

No. The Text Diff Viewer runs entirely in your browser. Your data is never sent to any server.

Does it work offline?

Yes. Once the page has loaded, the tool works without an internet connection.

Which browsers are supported?

All modern browsers — Chrome, Firefox, Safari, and Edge. No plugins or extensions required.

What algorithm does the free Text Diff Viewer use?

It uses a Longest Common Subsequence (LCS) algorithm to find the minimal edit distance between the two texts, similar to the Unix diff command.

Can I diff HTML or code with this tool?

Yes — any text is accepted. However, for syntax-aware code diffs with line numbers, consider the Diff Checker tool in the Developer Utilities category.

Text Diff Viewer

Compare two blocks of text side by side and highlight the differences.

Original text

Modified text

What is the Free Text Diff Viewer?

The free Text Diff Viewer compares two blocks of text side-by-side and highlights exactly what changed — removed lines in red and added lines in green. Unlike the developer-focused diff checker, this tool accepts plain prose, paragraphs, and any free-form text. Paste the original on the left and the modified version on the right to see the differences instantly.

→ Compare two versions of a contract, policy document, or terms of service.
→ Review changes in a blog post draft before publishing the updated version.
→ Check what was altered in a translated document compared to the source.
→ Spot unintentional edits between two copies of a template.
→ Verify that a revised email or letter only contains the intended changes.

How to Use the Free Text Diff Viewer

1 Paste the original (older) text into the left panel labelled "Paste the original text here…".
2 Paste the modified (newer) text into the right panel labelled "Paste the modified text here…".
3 Removed lines are highlighted in red; added lines in green; unchanged lines in grey.
4 Scroll through the diff output to review every change.
5 Edit either panel at any time — the diff refreshes instantly.

Key Features

🔴🟢
Color-coded diff

Red for removed lines, green for added lines — easy to scan at a glance.
⚡
Real-time comparison

Diff updates instantly as you edit either text panel.
📄
Plain-text friendly

Works with any free-form text — no code knowledge required.
🔒
100% private

Both text blocks stay in your browser. Nothing is uploaded.

Example Usage

Example Input

Original: "The cat sat on the mat."
Modified: "The dog sat on the mat."

Example Output

- The cat sat on the mat.
+ The dog sat on the mat.

Frequently Asked Questions about the Free Text Diff Viewer

What is the free Text Diff Viewer?: Compare two blocks of text side by side and highlight the differences.
Is the Text Diff Viewer free to use?: Yes, the Text Diff Viewer is completely free. No account, subscription, or signup is required — ever.
Does my data get uploaded anywhere?: No. The Text Diff Viewer runs entirely in your browser. Your data is never sent to any server.
Does it work offline?: Yes. Once the page has loaded, the tool works without an internet connection.
Which browsers are supported?: All modern browsers — Chrome, Firefox, Safari, and Edge. No plugins or extensions required.
What algorithm does the free Text Diff Viewer use?: It uses a Longest Common Subsequence (LCS) algorithm to find the minimal edit distance between the two texts, similar to the Unix diff command.
Can I diff HTML or code with this tool?: Yes — any text is accepted. However, for syntax-aware code diffs with line numbers, consider the Diff Checker tool in the Developer Utilities category.