Text Diff

Last updated: October 17, 2026  •  Published by: NOFYI Editorial Team  •  Category: Text Tools

Workspace

What Is the Text Diff Tool?

The Text Diff tool compares two texts and shows which lines were removed, added, or left unchanged. Paste the original text in one box and the revised text in the other, then compare them. Lines that differ are marked with a minus sign for the original and a plus sign for the revised version.

Use it to check an edited paragraph, compare two versions of a note, or spot what changed in a pasted snippet before you accept the edit.

How to Use the Text Diff Tool

  1. Open the Text Diff page.
  2. Paste the original text into the Original Text box.
  3. Paste the revised text into the Modified Text box.
  4. Click Process.
  5. Read the result: lines starting with – come from the original, and lines starting with + come from the revised text.
  6. Use Copy to copy the diff or Download to save it.
  7. Click Clear to empty both boxes and compare another pair.

Worked Example

Original: The cat sat on the mat.

Modified: The dog sat on the mat.

Observed output:

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

Why: the two lines are not identical, so the tool marks the whole original line as removed and the whole revised line as added, even though only one word changed from cat to dog.

Limitations

  • The comparison is line-level, not word-level. In the test, changing one word caused the whole line to be shown as removed and added. Read the two lines side by side to find the exact word that changed.
  • There is no side-by-side view and no word highlighting in the result. The output is a single list of – and + lines.
  • There are no diff options in the workspace, such as ignoring whitespace, ignoring case, or ignoring blank lines. Format the two texts the same way before comparing them if those differences do not matter.
  • There is no file upload in the workspace. Paste the two texts you want to compare.

Frequently Asked Questions

What do – and + mean?

A line starting with – is from the original text, and a line starting with + is from the modified text.

Does it highlight the changed word inside a line?

No. In the test, changing cat to dog marked the entire line as changed. Compare the – and + lines to spot the changed word.

Can I compare more than two texts at once?

No. The tool compares one original text with one modified text at a time.

Is my input saved?

No. The workspace is for the current page session. Copy or download the diff before you leave or reload the page.

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