Compare Two Texts Online
Paste an original and revised version to find line-by-line differences. Added and removed lines are highlighted locally, with options to ignore case or repeated whitespace.
Written and checked by TheToolNet Editorial Team · Last reviewed: October 10, 2026 · Editorial method
Green + rows exist only in the revised text. Red − rows exist only in the original. Unmarked rows match under the selected rules.
Compare two texts
Line differences
What this text comparison checks
The browser calculates a longest common subsequence of normalized lines. That makes insertions and deletions clearer than comparing line 1 only with line 1. It is useful for drafts, code snippets, configuration, lists, logs, and pasted document text.
The result is deliberately plain-text focused. It does not detect moved paragraphs as a special operation, highlight individual changed words, compare binary files, or decide whether two passages have the same meaning.
How to compare documents safely
- Copy the relevant plain text from each document.
- Paste the earlier version on the left and the later version on the right.
- Leave whitespace checking enabled when indentation or spacing matters.
- Review every red and green line in context.
- Use the document application's tracked-changes feature when layout, comments, or metadata also matter.
For contracts, policies, source code, and other consequential material, a text diff supports review but does not replace an appropriate professional or technical review process.
Frequently asked questions
Is my comparison uploaded?
No. Both texts and the calculated result stay in this browser tab.
Why does a changed line appear once red and once green?
A line replacement is represented as removing the earlier line and adding the revised line. This makes the exact source text visible on both sides of the change.
Can I compare very large files?
This page limits each side to 1,200 lines because the exact comparison requires increasingly more browser memory. Split larger files into logical sections or use a desktop diff tool.
Related text tools
Remove duplicate lines · Sort lists alphabetically · Normalize whitespace