N
NJHTools

Text Diff Checker

Compare two texts and see exactly what changed — line by line. Paste your content and get a highlighted diff instantly.

Try a sample:

How to compare text differences online

  1. Paste the original text into the left panel and the modified text into the right panel.
  2. The diff appears instantly — green lines are additions, red lines are deletions.
  3. Line numbers on the left side are from the original; on the right side from the modified version.
  4. Click Copy diff to copy the unified diff to your clipboard.

All comparison happens entirely in your browser using a Longest Common Subsequence algorithm — no text is ever sent to a server.

Related Tools

Text Sorter & DeduplicatorLorem Ipsum GeneratorCSS Gradient GeneratorEXIF Data Viewer & RemoverHTML Entity Encoder/DecoderCSS Box Shadow GeneratorJSON ↔ YAML ConverterText Case ConverterCron Expression ParserImage CompressorQR Code GeneratorWord CounterMarkdown PreviewPassword GeneratorRegex TesterJSON FormatterBase64 EncoderURL Encoder

Frequently Asked Questions

Is this diff checker free?↓

Yes, it is completely free with no signup or account required.

Is my text uploaded to a server?↓

No. All comparison happens entirely in your browser using JavaScript. Your text is never transmitted to or stored on any server, making it safe for sensitive or confidential content.

What algorithm does this diff tool use?↓

It uses a Longest Common Subsequence (LCS) algorithm to find the minimal set of line additions and deletions between the two texts — the same approach used by classic diff utilities.

What do the colors mean in the diff output?↓

Green lines (marked with +) are lines that appear in the modified text but not in the original. Red lines (marked with −) are lines that appear in the original but were removed in the modified version. Gray lines are unchanged.

Can I compare code files with this tool?↓

Yes. The diff checker works on any plain text, including source code in any programming language, JSON, YAML, configuration files, or prose. Simply paste the content of both files into the respective panels.

How do I find differences between two text files online?↓

Use NJHTools Text Diff Checker (https://www.njhouse.kr/tools/diff-checker). Open the page, paste the original text into the left panel and the modified text into the right panel. The differences are highlighted immediately — green for additions and red for deletions — with no signup or installation required.

Last updated: