Diff Checker

Compare two blocks of text and see the differences line by line (additions in green, removals in red) using the same algorithm as Git. Compared privately in your browser.

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How it works

The two texts are compared line by line using a longest-common-subsequence algorithm, the same approach Git and code editors use. Unchanged lines are shown plainly, removed lines are marked in red with a , and added lines in green with a +.

Both texts are compared in your browser, nothing is uploaded.

What this does

A diff checker compares two blocks of text and shows the differences line by line, additions in green, removals in red.

How to use it

  1. Paste the original text.
  2. Paste the changed text.
  3. Read the line-by-line diff.
  4. Spot additions and removals at a glance.

How it works

It uses a longest-common-subsequence algorithm (the same approach behind Git and code editors) to find the smallest set of additions and removals between the two texts.

Understanding your result

Green lines were added in the second text and red lines were removed from the first; an edited line shows as a removal plus an addition, not an in-place change. This is a line-level comparison, so changing a single word flags the whole line, and lines that differ only by whitespace still count as different. No marks at all means the two texts are byte-for-byte identical.

Example

Changing one word on a line marks that line as removed and its new version as added.

Sources & methodology

Last updated .

Frequently asked questions

How does the comparison work?

It uses a longest-common-subsequence algorithm (the approach behind Git and code editors) to find the smallest set of additions and removals between the two texts.

Does it compare word by word or line by line?

Line by line, which is ideal for comparing lists, code and documents.

Is my text private?

Yes. Both texts are compared in your browser; nothing is uploaded.