Text Diff Checker
Paste two versions of text below to see line-by-line differences highlighted.
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How this diff checker works
Paste two blocks of text and see exactly what changed — additions, deletions, and unchanged lines highlighted for quick comparison, computed entirely in your browser.
Line-based vs. character-based diffs
A line-based diff treats each full line as the unit of comparison, so a single-character change inside a long line shows the entire line as changed rather than highlighting just the edited word — useful for comparing whole files or configs, less useful for spotting a small typo fix in a paragraph. A character or word-level diff is more precise for prose but noisier for structured text like code or JSON.
Common causes of noisy, unhelpful diffs
Trailing whitespace, inconsistent indentation (tabs vs. spaces), and differing line-ending conventions (Windows CRLF vs. Unix LF) can make every single line appear changed even when the meaningful content is identical — this is one of the most common frustrations with diff tools generally. If a diff looks suspiciously like "everything changed" when you know only a small edit was made, check for one of these invisible-character mismatches before assuming the diff tool is broken.
Frequently asked questions
Why does every line show as changed when I only edited one thing?
Almost always invisible characters — trailing whitespace, mixed tabs/spaces, or different line-ending styles (CRLF vs LF) between the two texts. Check for those before assuming the tool is malfunctioning.
Can this ignore whitespace-only differences?
If the tool offers a whitespace-insensitive comparison mode, enabling it filters out exactly this kind of noise. Otherwise, normalizing whitespace in both texts first achieves the same result.
Is this suitable for comparing code, not just prose?
Yes, though a line-based diff (the most common approach) works better for code than a character-level diff would, since code's meaningful structure is organized by line.