Text Compare – Diff Checker That Highlights Every Change

Two versions of the same document, and you need to know exactly what changed: a contract returned from the other side, an article after an editor’s pass, a configuration file before and after troubleshooting. Reading both side by side and hoping to spot differences is slow and fallible. This diff checker compares your two texts line by line and shows the result with changes highlighted — lines only in the first version marked as removed, lines only in the second as added, and the summary counts telling you the scale of the edit at a glance. Paste the original on the left, the revised version on the right, and get a clear, colour-coded answer in a second.

Quick Answer: Paste the original and the revised text and the checker highlights added and removed lines, with a summary of how much changed.

Free Online Tool

Text Compare / Diff Checker

Original on the left, revision on the right — changes light up.

Original text

Revised text

0Lines added

0Lines removed

0Unchanged

How to Use the Text Compare / Diff Checker

Paste the original version into the left box.
Paste the new version into the right box.
Press Compare Texts.
Read the highlighted result: red lines were removed, green lines were added, plain lines are unchanged.
Check the summary counts to confirm the edit is the size you expected.

Key Features

Line-by-line comparison with clear red and green highlighting.
Summary counts for added, removed and unchanged lines.
Handles documents, lists, contracts and code snippets.
Runs entirely in your browser — confidential drafts stay confidential.
Free with no size limit for normal documents.

Best Practices and Tips

Clean both versions of stray spaces first if you only care about wording changes; whitespace differences at line ends are real differences to a diff.
For prose, compare paragraph by paragraph chunks if the document is huge — the highlights are easier to review in sections.
A completely rewritten paragraph shows as one removal plus one addition, which is the honest summary of a rewrite.
Keep the unchanged count in view: if it drops unexpectedly, more of the document changed than you were told.
For code, this line diff is a quick sanity check before reaching for full version-control tools.

Common Mistakes to Avoid

Comparing versions in different formats (one from PDF, one from Word) and drowning in formatting noise that is not a content change.
Assuming a small line count means a small edit — one ‘line’ can be a whole chapter if the paste has no breaks.
Skimming past a single-line change in a contract; price, date and liability edits are usually single lines.
Forgetting to scroll: long identical stretches can hide a small change far down the result.

Frequently Asked Questions

How does the comparison work?

The tool lines up the two texts and finds the longest set of lines they share in order. Lines outside that shared set are shown as removed (from the original) or added (in the revision). It is the same classic algorithm behind professional diff tools, simplified for pasted text.

Can it compare word by word instead of line by line?

This version compares whole lines, which suits documents and lists. A rewritten line shows as a removal plus an addition. For very long lines, breaking each version into paragraphs or sentences (one per line) gives a finer-grained comparison.

What counts as a change?

Any difference in a line’s characters, including capitalisation and extra spaces. If trailing spaces from a copy-paste create false alarms, run both texts through a space cleaner first, then compare.

Is it safe for contracts and private drafts?

Yes. The comparison runs with JavaScript in your browser tab; neither text is uploaded or stored anywhere, so confidential material never leaves your device.

How large can the texts be?

Articles, contracts and long documents compare comfortably. Extremely large pastes (entire books on both sides) may take a few seconds, but the result will still render.