Text Diff Checker
Compare two versions of text instantly and highlight what changed in a clear, honest way.
Paste an original version and a revised version to review line-by-line changes instantly. The summary and visual diff update in real time.
2
Added
1
Removed
2
Unchanged
Diff result
Recent history
Saved comparisons will appear here.
Why a text diff checker is useful
When two versions of a message, paragraph, or document look similar, it can still be surprisingly hard to spot what actually changed. A text diff checker solves that by comparing both versions and surfacing additions, removals, and unchanged lines in a format that is much easier to scan. That is helpful for editing copy, reviewing client feedback, comparing documentation updates, checking policy revisions, and verifying whether a small change introduced a larger unintended difference.
This page keeps the process simple and local. Paste the original text on one side, the revised text on the other, and the comparison updates right away in your browser. There is no hidden processing, no deceptive call to action, and no artificial waiting period. You get a practical summary and a readable output that supports real work. Because the comparison happens locally, the tool is also comfortable for private drafts and internal material.
Tips for better comparisons
For the clearest results, compare texts that use similar line breaks. If you are reviewing larger content, consider splitting long paragraphs into separate lines before comparing them. That makes additions and deletions easier to identify. You can also use the summary counts as a quick signal when you want to know whether a revision is minor or substantial before reading every line in detail.
A useful workflow is to save important comparisons to history as you iterate. That gives you a simple record of recent review sessions without sending anything to an outside service. This tool is designed to provide original value through clarity and utility rather than noise. It helps people understand revisions faster, communicate changes more confidently, and make better editing decisions with less friction.
Compare two versions of a text
This text difference checker compares an original text with a revised one, line by line. Lines that were added are highlighted green, removed lines red, and unchanged lines stay plain. Counts of added, removed and unchanged lines appear above the result.
How to use it
- Paste the original version into Original text.
- Paste the new version into Revised text.
- Read the diff result, which updates as you type. Lines are marked
+(added),-(removed) or=(unchanged). - Click Copy summary to copy the three line counts.
How it works
Both texts are split into lines. The checker finds the longest sequence of lines that appear in both texts in the same order (the longest common subsequence). Those lines are unchanged; every other line is marked as removed from the original or added in the revision.
Example: original Line one / Line two / Line three and revised Line one / Line 2 updated / Line three / Line four give 2 added, 1 removed, 2 unchanged. The edited line shows as one removed line plus one added line.
Tips for better comparisons
- Lines must match exactly. A changed capital letter, extra space or trailing space makes a line count as different.
- The checker compares whole lines, not single words, so put each sentence on its own line to pinpoint small edits.
- Use the same line breaks in both texts; reflowed paragraphs will show as entirely changed.
- Very long texts with thousands of lines can be slow to compare.
Saving to history
The comparison runs entirely in your browser. Save to history keeps your 10 most recent comparisons in this browser only (local storage), so you can reopen them later on the same device. Nothing is sent to a server, and Clear removes the saved list.
Frequently asked questions
Can it compare code?
Yes. Paste any plain text, including code or configuration files. It compares lines and does not understand programming syntax.
Does it highlight changed words inside a line?
No. A line that changed at all is shown as a removed line followed by an added line.
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