Compare Two Texts
Paste your original and revised text below, then click Compare. Added words highlight green, removed words highlight red. No signup — your text never leaves your browser.
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What Is a Text Compare Tool?
A text compare tool — also called a diff checker — takes two pieces of text and highlights every word that was added or removed between them. This tool runs entirely in your browser, so your documents stay private and the result is instant.
Who Uses Text Comparison?
- Writers and editors — spot every change between a draft and a revision without rereading every sentence.
- Students — verify a revised essay still contains required content and no sentences were accidentally cut.
- Legal teams — catch wording changes between contract versions. A single changed word can alter meaning significantly.
- SEO and content teams — log exactly what changed in an updated page for your edit history.
- Translators and proofreaders — confirm corrections were incorporated without introducing new errors.
Tips for Getting the Best Results
- Use Ctrl+A → Ctrl+C to copy your full document from Word or Google Docs, then paste directly.
- For long documents, compare section by section to keep the diff readable.
- Pair with the word counter to check if your revision hit your target word count.
- Use the character counter to verify revised ad copy or bios stayed within character limits.
How Word-Level Diff Works
This tool uses a Longest Common Subsequence (LCS) algorithm — the same family used by Unix diff and git. It finds the largest set of words shared between the two texts in the same order, then marks everything outside that shared set as either added or removed.
The result is a word-level view of every change, which is more readable than a character-level diff for prose and more precise than a line-level diff for short passages. The entire algorithm runs in JavaScript in your browser — no text is ever sent to a server.
Understanding the Similarity Score
The similarity percentage uses the Sørensen–Dice coefficient: (2 × shared words) ÷ (words in original + words in revision) × 100.
- 100% — texts are identical
- 70–95% — typical edited draft
- Below 50% — substantially rewritten
- 0% — no words in common
Texts up to 3,000 words per field are supported. For longer documents, compare section by section for best performance.
Frequently Asked Questions
Paste your original text in the left box and your revised text in the right box, then click Compare. Removed words appear in red with a strikethrough; added words appear in green with an underline. The similarity score and word counts update automatically.
A diff checker compares two pieces of text and shows exactly what changed between them. Writers use diff checkers to review editing passes, developers track documentation changes, and legal teams audit contract revisions without reading every word twice.
Yes. This tool is completely free and requires no account or signup. Paste text from any source — Word, Google Docs, PDFs, emails — and compare them instantly. Everything runs in your browser; nothing is uploaded to any server.