What the results show

Comparison — a quick verdict: Identical when the two texts match line for line, or Different when they don't.
Added — lines that appear in the changed text but not the original, highlighted in green with a + marker.
Removed — lines that were in the original but are gone from the changed text, highlighted in red with a − marker.
Unchanged — lines common to both, shown plainly for context. The two number columns are the line numbers in the original and the changed text.

How it works

Both boxes are split into lines, then compared with a longest common subsequence (LCS) algorithm — the same idea behind git diff. It finds the longest run of lines that appear in both texts in the same order and marks those as unchanged; everything else is reported as an addition or a removal. That keeps the shared parts aligned instead of flagging the whole rest of the file after a single inserted line.

Ignore case compares letters without regard to capitalization, and Ignore whitespace collapses runs of spaces and tabs and trims each line, so indentation or trailing-space changes don't register as differences. Both options only affect the comparison — the lines are always displayed exactly as you entered them. Swap sides flips the two boxes so you can view the diff from the other direction.

Frequently asked questions

Is my text uploaded or saved anywhere?

No. The comparison runs entirely in your browser. Your text is never sent to a server, logged, or stored — closing or reloading the page discards it.

Does it compare word by word or line by line?

Line by line. Each newline starts a new unit of comparison, so a line is counted as added, removed, or unchanged as a whole. To compare short snippets word by word, put each word on its own line.

What do the two number columns mean?

The left column is the line number in the Original text and the right column is the line number in the Changed text. An unchanged line has both; a removed line has only a left number, and an added line has only a right number.

Why does it show a dash instead of a result?

The dash appears when both boxes are empty — there is nothing to compare yet. Paste text into at least one box and the verdict and diff update instantly.

How do I ignore capitalization or spacing differences?

Turn on Ignore case to treat “Hello” and “hello” as the same, or Ignore whitespace to overlook differences in spaces, tabs, and indentation. You can enable either or both.

Is there a size limit?

There is no hard limit, and everything runs on your device. For very large pastes the tool automatically switches to a faster line-by-line comparison so the page stays responsive.