Text Compare — Free Online Diff Checker

What is a Text Compare Tool?

A Text Compare tool (टेक्स्ट तुलना), also called a diff checker, shows exactly what changed between two versions of a text. Instead of reading both versions line by line and hoping you spot every edit, you paste them side by side and the tool highlights every addition, deletion and modification. It is the same idea programmers use to review code changes, made simple for anyone: students checking an edited essay, editors reviewing a writer's changes, lawyers comparing contract drafts, translators checking updates to a source text, and teams comparing two exports of a list.

This free tool compares by lines, words or characters, can ignore differences in letter case and whitespace, and shows the result either side by side with line numbers or inline in a single flowing view. In side-by-side line mode, it goes one step further and highlights the exact words that changed inside each modified line. It uses the respected open-source jsdiff library, and everything happens in your browser — your text is never uploaded.

Key Features

• Three comparison levels — lines, words and characters.
• Side-by-side view with line numbers for both versions.
• Word-level highlights inside changed lines, so you see exactly what was edited.
• Inline view that shows removed and added text in one flow.
• Ignore case and ignore whitespace options.
• Statistics — added, removed and unchanged counts, plus a similarity percentage.
• Swap, clear and copy the diff in a simple +/− format.
• Private — comparison runs locally; only the open-source library is fetched.

How to Compare Two Texts — Step by Step

1. Paste the original (older) version in the left box.
2. Paste the changed (newer) version in the right box.
3. Pick the comparison level: Lines, Words or Characters.
4. Tick options such as Ignore case or Ignore whitespace if small differences don't matter.
5. Review the result below the stats. Untick Side-by-side for the inline view.
6. Copy the diff to share it, or Swap to see the change in reverse.

Lines, Words or Characters?

Line mode is the classic diff: any change inside a line marks the whole line as changed, and side-by-side view then highlights the changed words within it. Word mode ignores how text is broken into lines and focuses on which words changed. Character mode is the most precise but can look busy on heavily edited text.

Reading the Results

• Red text exists only in the original — it was removed.
• Green text exists only in the changed version — it was added.
• Uncoloured text is the same in both.
• In side-by-side line view, a modified line appears in red on the left and green on the right, with the specific changed words shaded darker.
• In inline line view, removed lines start with − and added lines with +, like a code review.

The counters show how many units were added, removed and unchanged in the current mode, and the similarity percentage gives a quick sense of how much the text changed overall.

How the Comparison Works

The tool uses jsdiff, a widely used open-source JavaScript library released under the BSD-3-Clause licence. jsdiff is based on the Myers diff algorithm, the same family of algorithms used by Git and many code review tools. It finds the shortest set of insertions and deletions that turns the original into the changed text, which produces the clean, human-readable highlights you see. The library is loaded from a public CDN the first time you compare; after that, all processing happens on your device.

Ignore Case and Whitespace

Sometimes differences are technically real but not meaningful. Ignore case treats “Hello” and “hello” as the same, which helps when one version was re-typed in a different style. Ignore whitespace skips differences in spaces and tabs — useful when code was re-indented or a document gained double spaces after full stops. Turn these options off when every character matters, such as passwords, codes or legal text.

Practical Uses

• Writing and editing — see exactly what an editor or teacher changed.
• Contracts and policies — check what changed between drafts before signing.
• Code review — compare two versions of a function, config or SQL query.
• Data checks — compare two exports of a list to find new or missing entries.
• SEO and content — compare old and new page copy or meta tags.
• Translation — find what changed in an updated source document.
• Plagiarism hints — see how closely two passages match (this is not a full plagiarism checker).
• Customer support — compare an error message or log line with a known good one.

Comparing Documents and PDFs

The tool compares plain text. To compare Word documents, Google Docs or web pages, select all the text, copy it and paste it into the boxes. Formatting such as fonts, colours and bold is not compared. For PDFs, copy the text if the PDF allows it, or use our PDF to Text tool first. When copying from PDFs, line breaks often differ between versions, so Word mode usually gives clearer results than Line mode.

Worked Example

The sample text loaded on this page compares two short paragraphs. In Line mode, side by side, the first line shows “brown” and “jumps” removed and “red” and “jumped” added; the second line is unchanged; the line “Your text is never uploaded.” appears only on the left (removed); and “A brand new fifth line.” appears only on the right (added). The counters report 2 added lines, 2 removed lines and 2 unchanged lines, giving a similarity of 50% (2 × 2 ÷ (2 × 2 + 2 + 2)). Switch to Word mode and the same edit is described in words instead — a more natural view for prose.

Common Mistakes to Avoid

• Putting the versions in the wrong boxes — additions will show as deletions. Use Swap to fix it.
• Using Line mode on re-wrapped paragraphs — every line looks changed; switch to Word mode.
• Ignoring whitespace in code where it matters — in Python or YAML, indentation changes meaning.
• Expecting moved text to be recognised as moved — it shows as removed in one place and added in another.

Troubleshooting

• “Could not load the diff engine” — check your internet connection the first time; the library is needed once per visit.
• “Large texts — press Compare” — automatic comparison pauses for very large inputs; press Compare to run it.
• Everything looks changed — line endings or wrapping differ; try Word mode or Ignore whitespace.
• Result is slow — character mode on huge texts is heavy; use Word or Line mode.
• Identical message but texts look different — an ignore option is ticked; untick it to see every difference.

Quick Glossary

• Diff: the set of differences between two texts.
• Unified diff: a format listing changes with − and + prefixes.
• Side-by-side diff: both versions shown in parallel columns.
• Myers algorithm: an efficient method for finding the shortest edit between two sequences.
• Whitespace: spaces, tabs and other blank characters.
• Similarity: the share of the text that is unchanged between the two versions.
• Version: one saved state of a document; comparing versions shows its history of edits.

Why Use This Text Compare Tool?

It combines a proven diff engine with clear side-by-side and inline views, word highlights inside changed lines, helpful ignore options and honest statistics — free, with no sign-up, and with your text kept private in your browser.

Text Compare (Diff Checker) — Key Facts

Frequently Asked Questions

Explore More Prompt Minds Tools

Text Compare (Diff Checker) works great alongside our other free tools. Every Prompt Minds tool runs entirely in your browser — no sign-up, no uploads, no watermarks. Browse all free tools.