Text Compare: Find the Differences Between Two Texts

What is a text compare tool?

A text compare tool, also called a diff checker, takes two versions of a text and highlights what was added, removed or changed between them. The word “diff” comes from the Unix diff utility, first released in 1974, and the same idea still powers GNU diffutils and git diff.

Use this text compare to see exactly what changed between two versions of the same document: a contract after the other side’s edits, an article after the client’s review, a config file after an update. The tool checks wording. Comparing the ideas or style of two different works, as a literature class does, is a different task.

How to compare two texts in 4 steps

To compare two texts, paste the original on the left, paste the new version on the right and read the highlighted result below. The result updates as you type.

1. Paste the original. Put the first version in Original text, or open a file with the upload icon or drag it onto the field.
2. Paste the new version. Put the second version in Changed text. The Differences panel updates as you type; for texts over 300,000 characters, press Compare instead.
3. Pick a mode. Words is the default and suits articles and contracts. Switch to Lines for code and lists, or to Characters for IDs, URLs and typos.
4. Refine and copy. Turn on Ignore case, Ignore spaces or Ignore punctuation to hide changes that don’t matter, then press Copy result to take the diff with you.

How to read the result

Red marks text that exists only in the original, green marks text that exists only in the new version, and everything without color is identical in both.

• Side by side shows the original on the left and the new version on the right, each with line numbers. A striped cell means the line was added or deleted as a whole.
• Inline puts both versions in one column: minus lines come from the original, plus lines from the new version. This view reads better on a phone.
• Highlights inside a line point to the exact words or characters that changed.
• The counter shows removed and added lines and a similarity score from 0 to 100%.
• Only changes folds long unchanged stretches into one row, keeping 3 lines of context around each edit. Click the row to expand it.

Word, line or character comparison: which mode to use

Compare by words for prose, by lines for code and structured data, and by characters for short strings where a single letter matters. In every mode the tool first aligns the two texts line by line, then marks what changed inside each changed line.

Lines mode marks each changed line as a whole, without highlights inside it, which keeps long code diffs easy to scan.

When to ignore case, spaces and punctuation

Turn on an ignore option when a difference is technically real but irrelevant to your task, so the result shows only the changes you care about.

• Ignore case treats “Price” and “price” as the same word. Useful when a text was retyped or a heading style changed.
• Ignore spaces hides double spaces, tabs, trailing spaces and changed indentation, common in code copied between editors and in text pasted from PDFs.
• Ignore punctuation skips commas, periods, quotes and dashes. Handy for transcripts and translations where only the words matter.

Ignored differences stay in the text itself. They are simply not highlighted and not counted as changes.

Who uses a text diff and for what

Anyone who works with more than one version of a text uses a text diff, from lawyers checking contract edits to developers reviewing a config change.

• Contracts and agreements. See whether the other side changed a deadline, an amount or a liability clause before you sign.
• Client edits. Compare your draft with the returned version instead of rereading every paragraph.
• Code and config files. Check what changed between two versions of a .htaccess, .env or JSON file when no version control is at hand. New redirect rules come ready from the 301 Redirect Generator.
• SEO copy. Compare the old and new title tag or meta description, then preview the new version in Google with the SERP Simulator.
• Translations. Compare a revised translation with the first draft.
• Your own drafts. Find what you changed between two saved versions of a thesis or a CV.

Is it safe to compare confidential text online?

With this tool, yes: the comparison runs in your browser, and the texts you paste are never sent to a server, stored or turned into a shareable link.

Many online diff tools process texts on their servers and keep saved comparisons behind public links. Here the algorithm runs locally, and closing the tab clears both fields, so the tool suits contracts, source code and documents under an NDA.

One rule applies to every online tool, this one included: remove passwords, API keys and card numbers before you paste a text anywhere.