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Diff Checker Online

Compare two versions of text and instantly see what changed. This diff checker highlights added, removed, and modified lines (or words/characters) without uploading anything.

Category: Text · URL: /tools/diff-checker-online.html
Tip: For paragraphs without newlines, try Split by → Words to pinpoint small edits.
Diff output
Unchanged: 0 Modified: 0 Added: 0 Removed: 0
Run a comparison to see results.
Related: Word Formatter Online (Free) Markdown Checker Online Markdown Formatter Online Markdown File Generator Free XML Diff Tool
Privacy: runs locally in your browser. No uploads, no tracking scripts.

How to use

Paste your “before” and “after” text, choose how to split (lines/words/characters), then run the comparison.

  1. Paste the original text on the left and the updated text on the right.
  2. Pick Split by (Lines is best for most cases) and optional ignores (trim, case, blank lines).
  3. Click Compare to see added (+), removed (−), and unchanged items.
  4. Use Copy diff to copy the result as plain text.
Keywords this page targets (natural cluster): diff checker online, text diff checker, compare two texts online, difference checker for text, online diff tool, compare text and find changes, line by line diff, word diff checker, character diff checker, git diff style text, ignore whitespace diff, case insensitive diff checker, side by side diff text, compare two versions of document, find added and removed lines, paste text compare tool, diff between two strings, show changes between texts, quick diff for notes, diff checker without upload
Secondary intents covered: Compare two pasted texts to see what changed, Spot added/removed lines between versions, Find a single changed word in a long paragraph, Ignore whitespace/case to avoid noisy diffs, Generate a copyable diff output for sharing, Quickly verify edits before publishing, Check if two texts are identical, Compare config-like content line-by-line, Swap inputs to review changes in reverse

FAQ

Is this diff checker online tool private?

Yes. The comparison runs in your browser; nothing is uploaded by this tool.

What does “Modified” mean in the summary?

It’s an estimate of changed items, counted when removals and additions appear in the same block (a replace instead of pure add/remove).

Can I compare by words or characters instead of lines?

Yes—use Split by to switch between Lines, Words, and Characters.

How do I ignore whitespace differences?

Enable Trim and/or Collapse spaces to reduce whitespace-only changes.

Why are unchanged lines hidden?

Hide unchanged is on by default to keep output compact. Turn it off if you want full context.

Is the output compatible with Git diff?

It’s a simple text format with +/− markers for easy copying, not a full unified diff patch.

What if my text is very large?

Very large comparisons can be slow in the browser. Diff smaller sections, split by lines, and hide unchanged items.