What is the difference between word-level and line-level diff?

A line-level diff marks whole lines as added or removed. A word-level diff looks inside each paired change and highlights the exact words that differ, so a single changed word in a long sentence is immediately visible instead of hiding inside two full-length colored lines.

What do the ignore case and ignore whitespace options do?

Ignore case treats "Hello" and "hello" as identical. Ignore whitespace discounts leading and trailing spaces on each line, so indentation or stray spaces alone will not mark a line as changed. Both options affect the comparison only - the original text is always displayed.

What is the difference between unified and side-by-side view?

Unified view lists changes in one column with + and − markers, like a git diff. Side-by-side view places the original on the left and the changed text on the right, pairing each removed line with its replacement so you can read across. Both views include word-level highlighting.

How is this different from the Text Compare tool?

Text Compare does a fast line-by-line comparison in a single unified list - ideal for a quick check of what changed. Diff Checker adds word-level highlighting inside changed lines, a side-by-side view, line numbers, ignore options, and a copyable diff. Use Text Compare for a quick scan; use Diff Checker when you need to see exactly which words changed.

Is my text stored anywhere?

No. All comparison happens in your browser. Neither text is sent to any server, and nothing is retained after you leave the page.

Is there a text length limit?

For typical documents, comparison is instant. For very large inputs, the word-level highlighting is skipped automatically and only the line-level diff is shown, which keeps the tool responsive.

Diff Checker - Find the Difference Between Two Texts

Advanced diff checker with word-level highlighting and side-by-side view. Compare two texts free in your browser - private, no signup.

🔒 Your text stays in your browser - nothing is sent to our servers

Original Text0 chars / 0 words / 0 lines

Changed Text0 chars / 0 words / 0 lines

Ignore caseIgnore whitespaceNormalize line endings

How to Use

Three steps to get started

Paste original text

Paste the original (older) version of your text in the left field.

Paste changed text

Paste the changed (newer) version in the right field. Swap ⇄ flips the two.

Click Compare

Review the diff: added words in green, removed words in red, in unified or side-by-side view.

About This Tool

An advanced diff checker for editing, review, and QA

A diff checker compares two versions of a text and shows exactly what changed between them. This one goes a step further than a plain line diff: inside every changed line it highlights the individual words that were added or removed, so you can see the one edited verb in an otherwise untouched sentence - the kind of change that is nearly invisible when two full lines are simply colored red and green.

Choose between a unified view, which stacks the diff in a single column with + and − markers the way git diff does, and a side-by-side view, which pairs the original line on the left with its replacement on the right so you can read across the change. Both views carry the word-level highlighting, line numbers for reference, and a one-click copy of the diff as plain unified text.

Comparison options handle the noise that makes diffs hard to read. Ignore case skips capitalization-only edits, ignore whitespace skips indentation and stray spaces, and normalize line endings (on by default) prevents a Windows CRLF file from being reported as fully changed against an identical Unix LF file.

When to reach for a diff checker

Proofreading revisions - confirm a proofreader's "light pass" really was light, and see each substitution at word level
Reviewing edited drafts - check what an editor, colleague, or AI assistant actually altered in your writing
Code and config review without git - compare two versions of a snippet, a config file, or a log when you are not in a repository
Contract redlines - verify that clauses come back unchanged except where marked, with every modified word highlighted
Changelog writing - turn two versions of a document into an accurate list of what changed
Data QA - confirm an export, migration, or copy-paste reproduced a text exactly

For a quick line-only scan of what changed, the lighter Text Compare tool also works well; this Diff Checker is the version to use when the precise words matter. Everything runs in JavaScript inside this page - no upload, no server, no copy retained - so confidential drafts, contracts, and credentials stay on your machine.

FAQ

Frequently Asked Questions

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