What the comparison actually does

Put the first version in the left panel and the second version in the right panel. The tool compares them line by line and then, inside every line that changed, it compares the words as well. That second pass is what makes the result useful: instead of colouring a whole line red and green, it marks the words that were really removed and the words that were really added.

  • Added lines appear in green and only exist in the new version.
  • Removed lines appear in red and only exist in the old version.
  • Changed lines appear on both sides, with the differing words highlighted inside them.
  • Unchanged lines stay plain, so the shape of the document is still readable.

The counter above the result tells you how many lines were added, removed, changed and left alone, which is enough to tell whether a change was a small edit or a rewrite.

Reading the two views

There are two ways to read the result, and both show the same comparison.

  • Side by side puts the original on the left and the changed text on the right, with the line numbers of each side. It is the clearest view when the two versions are the same length and you are hunting for one specific edit.
  • Inline merges both versions into a single stream. Unchanged lines are shown once, removed text is struck through and added text is marked in green. It reads like a changelog and works better on a narrow screen.

Two switches that cut through the noise

Most "no difference" results are formatting, not meaning. Two options remove that noise:

  • Ignore whitespace changes treats runs of spaces and tabs as the same, so a re-indented file is reported as unchanged. A file that has been through a formatter can then be compared against the original without the whole document lighting up.
  • Ignore letter case treats Error and error as the same, which matters when only the capitalisation was touched.

Both switches work on the comparison itself, not on the text you see, so the panel always shows exactly what you pasted.

How to use it

  1. Paste the original text into the left panel, or load it from a file with the button underneath.
  2. Paste the changed text into the right panel.
  3. Switch on the ignore options if the difference is only formatting.
  4. Read the result, then copy or download it. The copied text is a plain diff that can be pasted into a message, a ticket or a pull request.

Need to clean the text up before you compare it? The Text Cleanup tool removes stray spaces and blank lines first, which makes the comparison much easier to read.

Good to know

  • Nothing is uploaded. Both panels are compared inside the page, so a contract or an internal document never leaves your device.
  • Each panel accepts a file, which is quicker than pasting a long document. Plain text, Markdown, CSV and JSON files all work.
  • The swap button exchanges the two panels in one click, so you can check the comparison the other way round without re-pasting.
  • The word level pass marks whole words, so a change inside a long identifier is reported as one word being replaced rather than as a whole line.
  • To see how much text you are actually dealing with, the Word Counter reports words, characters and reading time for either panel.
  • Very large documents are handled in the same way, but the first comparison of a long file takes a moment while the lines are indexed.