Text Compare
Find the differences between two texts line by line
Text Compare: What Changed Between Two Versions?
What changed in the new contract draft? Don't scan by eye — let the colored diff tell you.
Spotting the difference between two versions of a text by eye is slow and unreliable: a one-word change hides easily across pages. This tool brings the diff method developers have relied on for decades to everyone. Paste the original and the changed text into the two boxes, hit Compare, and you get a unified view with removed lines marked red (−) and added lines green (+). The boxes above summarize the similarity percentage plus the counts of added, removed and unchanged lines. Contract revisions, essay and paper versions, translation checks, code snippets — it works for any text that exists in two versions. The comparison runs entirely in your browser; your texts are never sent to a server, so it's safe even for confidential documents.
Features
Line-by-Line Diff
Added in green, removed in red — see it at a glance.
Similarity Score
Learn exactly how much the two texts overlap.
Fully Private
Texts never leave your device — nothing is uploaded.
Up to 2000 Lines
Compares even long documents in seconds.
Diff Guide
How it works
- Texts are split into lines and the longest common subsequence (LCS) is found
- Old lines missing from the common sequence are marked removed (−)
- New lines missing from it are marked added (+)
- Similarity = 2 × common lines ÷ total lines
Use cases
- Auditing contract and proposal revisions
- Comparing essay, paper and report versions
- Checking a translation against its source
- Finding differences in code, configs and lists
Frequently Asked Questions
What method does the comparison use?
Line-based LCS (longest common subsequence) — the same approach version-control tools like git use. Lines present in both texts are matched; the rest are marked added or removed.
How is the similarity percentage calculated?
Twice the number of common (unchanged) lines divided by the total lines of both texts. 100% means the texts are identical; 0% means no line is shared.
Does it show word-level differences?
The tool works at line level: if one word in a line changes, the line appears as 'removed + added'. For finer results on long paragraphs, split the text so each sentence sits on its own line before pasting.
Are my texts sent to a server?
No. The entire comparison runs in your browser with JavaScript. Confidential documents like contracts are safe to compare; drafts are remembered only on your own device.
Do case and whitespace affect the diff?
Yes — the comparison is exact: 'Hello' and 'hello' are different lines, and even a trailing space creates a difference. For legal texts, that's precisely the sensitivity you want.
Can I compare Word or PDF files?
There's no direct file upload; open the file, copy its text and paste it into the boxes. Formatting (bold, colors) isn't compared — only the text content is.