The Fastest Free Online Diff Checker

Whether you are comparing two versions of a document, reviewing an edit, checking if a contract clause changed, or spotting the difference between two code snippets, a reliable diff checker saves you enormous time. Our free online diff checker highlights every insertion, deletion, and modification between two blocks of text in real time: no page load, no server round-trip, no account required. All comparison logic runs entirely inside your browser. Nothing you paste is ever sent to our servers. We keep zero logs. Use it as many times as you need, for as long as you need, it is free forever with no usage limits.

Three Diff Views: Pick What Works for You

Split View (Side by Side)

The original text appears on the left panel and the changed text appears on the right. Additions are highlighted in green, deletions in red. This view is best when you want to read both versions simultaneously: ideal for comparing document drafts, legal clauses, or translated paragraphs.

Unified View

Both texts are merged into a single column, with added lines prefixed by + and removed lines by -. This is the classic diff format used by Git and command-line tools: familiar to developers and version control users.

Word-Level Diff

Instead of highlighting entire lines, word-level diff zooms in to show exactly which words changed within each line. This is the most precise view: perfect for proofreading edits, comparing near-identical sentences, and catching single-word substitutions that line-level diff might obscure.

Diff Statistics at a Glance

Below the comparison panels you will see a summary of:

• Additions: the count of new lines or words added
• Deletions: the count of lines or words removed
• Unchanged: the count of lines that are identical in both versions

These numbers give you an instant sense of how much has changed between two versions without reading every line.

Who Uses a Diff Checker?

• Developers: compare code snippets, config files, or API responses without a full IDE
• Writers & editors: review edits made to an article or manuscript and see exactly what changed
• Legal professionals: compare contract versions to spot added or removed clauses
• Translators: check that a revised source text aligns with a previous translation
• QA testers: compare expected and actual output from an application
• Students: review feedback on an essay draft vs. the original submission
• Teachers: compare a student's original submission with a revised version to catch plagiarism edits

How to Compare Two Texts Online

1. Paste the original text into the left panel (labelled "Original").
2. Paste the changed text into the right panel (labelled "Changed").
3. The diff updates automatically: additions appear in green, deletions in red.
4. Switch between views using the tabs above the result: Split, Unified, or Word.
5. Copy the diff output using the copy button if you need to share the result.

Auto-Diff as You Paste

By default, the comparison updates automatically as soon as you paste or finish typing in either panel: no "Compare" button needed. This makes it fast to iterate: paste the second version, see the result immediately, tweak the first, and the diff refreshes in real time.