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Text Diff Checker

Compare two texts line by line and see exactly what was added or removed.

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diff.exe

Diff Checker

Compare two texts line by line and see exactly what was added or removed.

Starts in your browser. Instructions are below.

How to use Diff Checker

  1. 01Paste the original text into the Original text box and the changed version into Changed text.
  2. 02The comparison runs as you type and marks each line as added, removed, or unchanged.
  3. 03Switch between Unified and Side by side view, and check the totals above the diff.

About Diff Checker

This diff checker compares two blocks of text line by line and highlights exactly what changed. It uses a longest-common-subsequence algorithm, the same approach behind the diff command in version control tools, so inserting a line does not mark everything after it as changed.

Paste your original text on one side and the edited version on the other. Added lines are highlighted in one color and removed lines in another, with a running count of additions, removals, and unchanged lines above the result.

Use it to compare two drafts of a document, two versions of a config file, or a before-and-after of a block of code. Because it compares whole lines, reformatting a paragraph can look like a large change even when the words barely moved.

Frequently asked questions

Is my text uploaded anywhere?
No. The comparison happens entirely in your browser.
Can it compare code?
Yes. Line-by-line comparison works for code, config files, and prose equally well.
Why is a whole line marked as changed when only one word moved?
The diff compares whole lines, so any edit within a line marks that line as changed rather than just the edited word.
What is the difference between unified and side-by-side view?
Unified shows one column with + and - markers; side by side shows the original and changed text in two columns.

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