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Text Diff Checker

Compare two texts and see every addition and deletion highlighted, by word, line, or character.

Compared live as you type. Nothing leaves your browser.

Compare by

View

Differences

The comparison appears here once both texts have content.

How to compare two texts online

  1. Paste both texts

    Put the original version in the first box and the edited version in the second. The comparison starts on its own once both boxes have content.

  2. Read the highlighted result

    Deleted text appears with a red tint and strikethrough, added text with a green tint, and a summary line counts the additions and deletions.

  3. Switch the granularity

    Choose Words for prose, Lines for code and lists, or Characters to catch every small edit, and the view updates instantly.

  4. Copy the diff

    Copy diff puts a plain-text version on your clipboard with plus and minus line prefixes, ready for a ticket, an email, or a review comment.

Why use this tool

Three comparison granularities

Compare by words for prose revisions, by lines for code and lists, or by characters when a single stray space matters.

Inline and side-by-side views

Read both versions merged into one column with red deletions and green additions, or switch to two aligned columns with line numbers to compare them row by row.

Unified copy output

One click copies the comparison as plain text with plus and minus line prefixes that paste cleanly anywhere.

Live as you type

There is no compare button. The result recomputes shortly after you stop typing in either box, at any granularity.

Ignore whitespace or case

Optionally treat lines that differ only in spacing or indentation as equal, or treat uppercase and lowercase as the same, and the comparison recomputes instantly.

Confidential text stays local

Both texts are compared on your device. Contracts, drafts, and code are never uploaded or stored.

About this tool

This text diff checker compares two versions of a text and shows every change at a glance. The inline view merges both versions into one column, with deleted passages in a red tint and strikethrough and insertions in a green tint. The side-by-side view instead places the original and the edited text in two aligned columns, each with its own line numbers, so you can read them row by row the way a code review does; long stretches of unchanged lines collapse to a few context lines that expand on demand. There is no compare button: paste or type into either box and the result refreshes a moment after you stop, so you can edit one side and watch the differences shrink as the versions converge.

The right granularity depends on what changed. Words mode suits prose: contract revisions, copy edits, and rewritten paragraphs read naturally because whole words are marked rather than fragments. Lines mode matches how code review works, tinting each changed line end to end, which makes it the pick for code snippets, config files, and lists. Characters mode flags every individual character, catching a doubled space, a swapped punctuation mark, or a sneaky whitespace edit that the other modes would treat as no change at all. Whichever mode is on screen, Copy diff produces a plain-text, line-by-line version with plus and minus prefixes, the format reviewers and ticket systems already understand.

Everything runs in your browser, so unreleased announcements, legal drafts, and private code never leave your device. A few pairings come up often: when the two versions are JSON, run both through the JSON formatter first so the comparison shows real changes instead of formatting noise; after accepting edits, the word counter confirms the new length; and if the only differences are stray spaces, the whitespace remover cleans them up in one pass.

Frequently asked questions

How does the text diff checker work?
Paste the original text into the first box and the changed text into the second. Once both have content, the tool compares them automatically and renders one combined view: red with strikethrough for deleted text, green for added text. Editing either box updates the result a moment later.
Should I compare by words, lines, or characters?
Words is the default and reads best for prose such as articles, emails, and contracts. Lines marks whole changed lines, which suits code and lists. Characters flags every individual character change, including whitespace and punctuation, when precision matters more than readability. In the side-by-side view the same setting controls how edits within each changed line are highlighted.
Can I compare the two texts side by side?
Yes. Set the view to Side by side to see the original on the left and the edited text on the right, aligned line by line with line numbers on each side. Added, removed, and changed lines are tinted, blank filler rows keep matching lines level, and long runs of unchanged lines collapse to a few context lines you can expand. A summary reports the additions, deletions, and how much stayed unchanged.
Can I ignore whitespace or letter case?
Yes. Turn on Ignore whitespace to treat lines that differ only in spacing or indentation as equal, or Ignore case to treat uppercase and lowercase as the same. Both options recompute the comparison instantly in either view, and the Swap button flips the original and changed sides.
Is my text uploaded anywhere?
No. Both texts are compared entirely in your browser. Nothing is sent to a server, stored, or logged, which makes the tool safe for contracts, unpublished drafts, and private code.
What format does Copy diff produce?
A plain-text, line-based comparison: removed lines start with a minus sign, added lines with a plus sign, and unchanged lines with a space. It pastes cleanly into tickets, emails, and review comments.
Why does it say there are no differences when the texts are not identical?
Words mode treats runs of whitespace as equivalent, so texts that differ only in spacing can compare as equal. Switch to Characters to surface whitespace-only and punctuation-only changes.
Is there a size limit?
There is no fixed limit, and typical documents compare instantly. Extremely large texts with very heavy edits can stop the comparison early at fine granularities; if that happens, Lines mode or comparing smaller sections works reliably.

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