Compare Two Texts Online (Text Diff)
This free text comparison tool shows the differences between two blocks of text in real time. Paste the original version on the left and the modified version on the right, and removed lines are highlighted in red while added lines are highlighted in green — like a lightweight, in-browser version of a code diff.
It is useful for reviewing document edits, comparing configuration files, spotting changes between two versions of a paragraph, or checking what changed between two exports. Both texts stay in your browser and are never uploaded.
How to use Text Diff
- Paste the original text into the left box.
- Paste the modified text into the right box.
- The Differences panel updates automatically as you type — removed lines show with a red strikethrough, added lines show in green.
- Use the copy buttons to grab either text, or Clear to start over.
How the comparison works
The tool compares the two texts line by line: lines that are identical at the same position are treated as unchanged, while any position where the texts disagree produces a removed line (from the original) and an added line (from the modified text). This straightforward positional comparison is fast and easy to read, but note that inserting a single line near the top shifts every following line, which a positional diff reports as multiple changes — the same behavior you may know from simple diff modes in other tools.
Related terminology
- Diff
- Short for difference — a report of what changed between two versions of a text or file, traditionally produced by the Unix diff program.
- Added / removed lines
- Lines present only in the modified text (added, conventionally shown in green with a plus sign) or only in the original (removed, shown in red with a minus sign).
- Line-based comparison
- A diff strategy that treats each line as the unit of change, as opposed to word- or character-level diffs.
Frequently asked questions
- How do I compare two texts online?
- Paste the original text in the left box and the new text in the right box. The differences appear instantly below, with removed lines in red and added lines in green.
- Is this the same as the diff command or GitHub's diff view?
- It is the same idea — a line-by-line comparison with additions and removals highlighted — in a simple form. This tool compares lines by position, so it is best suited to texts of similar structure.
- Is there a size limit?
- There is no hard limit; comparison happens in your browser, so very large texts are only constrained by your device's memory.
- Are my documents uploaded anywhere?
- No. The comparison runs entirely client-side, which makes the tool safe for contracts, unpublished drafts, and other sensitive text.