Text Diff Checker
Fill Text A and Text B (samples start as one / two / three versus one / TWO / three). The tool splits each box on newlines, aligns by line index, and prints = when both sides match or ! when they differ, using the form left | right.
Updated 2026-08-03 · text
About this tool
This checker is a simple line-aligned diff, not a word-level or character-level patch. Extra blank lines on one side still occupy a row. Comparison is case-sensitive, so two and TWO are marked different. There is no merge or apply-patch button.
How to use
- Open the checker: Load this page so Text A, Text B, and the result block appear.
- Paste the first version: Enter the original content in Text A (sample has three lines).
- Paste the second version: Enter the revised content in Text B for the same line order.
- Read the markers: Scan the result for = matching pairs and ! differing pairs in left | right form.
Common use cases
- Spot edits between two draft paragraphs before publishing.
- Compare config snippets or lists when only a few lines should change.
- Review student answers against a key line by line.
Tips
- Keep related lines in the same row order; the tool does not reshuffle unmatched blocks.
- Look for ! prefixes to find mismatches; = means that line pair is identical.
FAQ
What do = and ! mean?
= means both lines match. ! means that line index differs between A and B.
Is the comparison case-sensitive?
Yes. Changing case alone, such as two versus TWO, produces a ! row.
Does it highlight word-level changes?
No. It compares whole lines and prints both sides separated by |.
Are my texts uploaded?
Diffing runs in your browser as you type; no account is required.