Text Diff Checker

Paste an original and a changed version of any text — notes, code, contracts or essays — and get a clear line-by-line comparison. Added lines are highlighted in green, removed lines in red, so you can spot every change in seconds. The comparison runs entirely in your browser.

Both texts stay in your browser. Nothing is uploaded or saved anywhere.

How to use Text Diff Checker

  1. Paste the original version into the left box.
  2. Paste the new version into the right box.
  3. Press “Compare” to see a highlighted line-by-line result.
  4. Copy the difference list if you need to share what changed.

About this tool

When two versions of a document exist, finding what changed between them by eye is slow and error-prone — especially for long texts where a single word may differ.

This tool compares the two versions line by line using the same approach as professional version-control systems, then highlights exactly what was added and removed.

Frequently asked questions

How does the comparison work?
Both texts are split into lines and matched using a longest-common-subsequence algorithm — the same technique behind developer diff tools. Unmatched lines are reported as additions or removals.
Does it compare word by word?
The comparison works at line level. If one word changes inside a line, that whole line appears as a removal plus an addition, which makes the change easy to locate.
Is there a size limit?
For a fast, responsive result the first 400 lines of each version are compared. For most documents, essays and code files that covers everything.
Can I use it for code?
Yes — any plain text works, including code, CSV rows and logs. Formatting like colors in the source is ignored; only the text content is compared.
Is my text kept private?
Yes. The diff is calculated locally in your browser, which makes this tool safe even for confidential documents.

Related tools

Remove Duplicate Lines Delete repeated lines from a list and keep only unique entries. Text Sorter Sort lines alphabetically, by length, numerically, or shuffle them. Word Counter Count words, characters, sentences and paragraphs in your text.

Browse all Text Tools →

How to use Text Diff

Enter or paste your text into the Text Diff field. Choose the operation — counting, cleaning, sorting, or converting — and apply it. Review the result and copy it back for use.

Practical benefits

Frequently asked questions

Is this tool free to use?
Yes. Text Diff is fully free with no account or subscription required.
Does it upload my files?
No. All processing occurs locally within your browser session.
Can I use this for professional projects?
Yes, the tool is designed for both casual and professional use. Always verify critical outputs.