The diff checker compares an original and a changed version of a text and highlights what was added, removed or edited. Removed lines are shown in red, added lines in green, and inside an edited line the exact words that changed are marked, so a single corrected comma is easy to spot.
Use it to review edits to a contract or essay, compare two versions of a config file or source code, or check what a colleague changed in a document. The comparison runs in your browser with a Myers diff algorithm, the same approach used by Git, and neither text is sent anywhere.
How to use the Diff Checker tool
- Paste the original text into the left box.
- Paste the changed text into the right box. The comparison runs automatically.
- Choose Side by side or Inline view.
- Tick Ignore case or Ignore whitespace to skip differences you do not care about.
- Turn on Only show changes to hide long unchanged parts, or copy the diff as text.
Why use ToolOrca Diff Checker
- Line-by-line comparison with word highlighting
- Side-by-side and inline (unified) views
- Ignore case and whitespace options
- Line numbers for both versions
- Hide unchanged lines with context
- Private: texts never leave your browser
How the comparison works
The tool finds the longest sequence of lines the two texts have in common and treats everything else as additions or deletions. When a block of removed lines is directly followed by added lines, they are paired up as edited lines and compared again word by word, which is where the darker highlights come from.
Moving a paragraph shows up as a deletion in one place and an addition in another, because a line-based diff does not track moves. If a whole document appears changed, the line endings or indentation may differ; try Ignore whitespace.
Reading the result
Red rows exist only in the original, green rows only in the changed text, and rows with both colours are lines that were edited. The summary above the table counts changed, added and removed lines. Copy diff gives a plain-text version where removed lines start with “-” and added lines with “+”.
Frequently asked questions
Is it safe to compare confidential documents?
Yes. Both texts are compared by JavaScript in your own browser. Nothing is uploaded, logged or stored.
Can I compare code with this diff checker?
Yes. It works with any plain text, including source code, JSON, CSV and config files. Turn on Ignore whitespace to skip indentation changes.
Can I compare Word or PDF files?
Copy the text out of each document and paste it into the two boxes. Formatting such as bold or fonts is not compared, only the words.
How large can the texts be?
Texts of several thousand lines compare in a fraction of a second. Very large inputs are compared when you click Compare instead of on every keystroke.
Why is a moved paragraph shown as deleted and added?
Line-based diffs, including Git’s, record moves as a deletion plus an addition. The words themselves are unchanged, they are just in a new place.