Updated · Built and checked by the PlinzoTools team, formulas tested against published sources
Compare two blocks of text and highlight every line that changed.
Enter both texts above to see the comparison.
This tool compares two versions of a text -- an original and an edited version -- and highlights exactly what changed at the word level: additions, deletions, and what stayed the same, rather than just telling you the texts are different.
Paste your original text into the left box and your edited/new version into the right box. The comparison updates as you type, showing a summary count of additions, deletions, and unchanged words, plus a detailed view you can switch between side-by-side (original and new shown in separate columns) or unified inline (both versions merged into one flowing view with changes marked).
The tool uses a word-level Longest Common Subsequence (LCS) algorithm -- the same category of algorithm behind most code-diff tools -- to find the longest sequence of words shared between both texts, then marks everything else as either removed (only in the original) or added (only in the new version).
Whitespace is preserved as its own token type, so line breaks and spacing differences are reflected accurately rather than being silently collapsed.
Writers and editors comparing a revised draft against the original to see exactly what an editor changed. Anyone comparing two versions of a document, contract, or policy to spot substantive wording changes without manually re-reading both in full.
This performs a word-level comparison, not a character-level one -- a single-letter typo fix will show as a full word removed and a full word added, not a highlighted individual character change. The comparison runs entirely in your browser; your text is never uploaded.
Suppose the original says "The meeting is on Monday at 3 pm in room 4" and the revised version says "The meeting is on Tuesday at 3 pm in room 7". The checker shows "Monday" removed and "Tuesday" added, then "4" removed and "7" added, while every other word is marked unchanged. Even in a long document, this kind of highlighting lets you find a changed date or figure that a quick read might miss. The summary counts tell you at a glance whether an edit was light (a handful of changes) or a heavy rewrite.
Before comparing, make sure both versions come from the same source format. Text copied from a word processor may contain non-breaking spaces, curly quotes, or different line-break conventions that show up as differences even when the wording looks identical. Because whitespace is tracked, an extra space or a changed line break will register as a change. If you only care about wording, normalize spacing in both boxes first. Straight quotes versus curly quotes are another common source of noise, and the tool treats them as different characters.
The comparison is word-based, so it does not understand meaning, formatting such as bold or headings, or images. Only the plain text you paste is compared. Very large documents may take longer to process because the algorithm compares every word against every other, so for book-length text compare it in sections.
Side-by-side shows the original and new text in two separate columns for direct comparison; unified inline merges both into one continuous view with additions and deletions marked in place.
Word level -- changes are detected and highlighted by whole word, not individual character, which keeps the comparison readable for normal prose editing.
It works on any plain text, but it's optimized for prose-style word-level changes rather than line-level code diffing -- a dedicated code diff tool may be better suited for comparing source code specifically.
Hidden differences such as extra spaces, non-breaking spaces, or curly versus straight quotes count as changes. Normalize both texts before comparing.
They typically appear as deleted at the old position and added at the new one, because the comparison follows word order and does not detect moves.
Yes, but processing time grows with size. For very long text, split it into sections and compare each pair separately.
No. Only plain text is compared, so pasted formatting is ignored and only the words and spacing count.