Text Compare Online
Compare two versions of a text and highlight additions and deletions. Choose word, line or character comparison, with both versions displayed side by side.
Exact, case-sensitive comparison: whitespace is not ignored. Maximum 100,000 UTF-16 code units per input. Very large comparisons use a clearly labelled block overview. Inputs are never silently truncated.
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Comparison results
Original · deletions marked
Revised · additions marked
Optional markers: · = ordinary space, ⇥ = tab, ↵ = line break. Markers change the display only. A replacement is shown as a deletion plus an addition. Moved text may also appear this way.
How to compare two texts
1. Paste both versions
Place the earlier text in Original and the updated text in Revised.
2. Choose a level
Use words for drafts, lines for structured text or characters for small edits.
3. Review the differences
Click Compare texts, inspect the highlights, then copy the revised text or download a report.
Choose the right text comparison level
Word comparison for drafts
Word mode separates letter-and-number sequences, punctuation and whitespace into comparison units. It is useful for reviewing edits to paragraphs, descriptions and messages. Its unit counts are not word counts: spaces and punctuation also contribute units. Languages without spaces between words may need character mode.
Line comparison for structured text
Line mode compares complete lines, keeping each line’s ending with its content. Use it for lists, configuration snippets and other text organized by lines. A single changed letter may highlight the entire line; switch to character mode for a closer look. This is a plain-text comparison, not a code parser.
Character comparison for small changes
Character mode compares Unicode code points. It can reveal changes in spelling, accents, punctuation and spacing. A visible character can contain multiple code points, so a combined accent or emoji sequence may be highlighted in parts.
What the highlights mean
Deleted content is struck through on the original side. Added content is underlined on the revised side. A substitution appears as a deletion and an addition rather than a separate replacement category. Moving a sentence may also appear as deleting it in one position and adding it in another.
Large-text comparison
Detailed comparison uses a longest-common-subsequence calculation on the selected units after removing a shared beginning and ending. If the remaining comparison would exceed one million table cells, the tool switches to a block overview: it keeps that shared beginning and ending and marks the middle sections as changed.
The overview preserves both texts, but it may highlight matching content inside the middle sections. Its counts describe the displayed blocks, not a minimal edit sequence. The result clearly identifies when this fallback is used.
Exact text differences, not plagiarism detection
The tool compares the text you provide. It does not search the web, determine authorship or measure semantic similarity. Case, whitespace and Unicode representation differences are significant. Browser textarea handling can normalize pasted line endings to LF; this is not a byte-for-byte file comparison.
To measure length and Unicode details, use the Character Counter. To check word counts and estimated reading time, use the Word Counter.
Privacy and text handling
This tool’s code compares your text locally in your browser. It does not send inputs to an API or save them in browser storage. Copying uses your clipboard only when requested, and the TXT report is generated locally.
Your browser, extensions and other scripts on the website have their own behavior, which this tool does not control.
Frequently asked questions
Does it ignore capitalization or extra spaces?
No. This version compares the inputs exactly as held in the textareas. Capitalization, spaces, tabs and line breaks can produce differences.
Can I compare an empty text with a populated text?
Yes. If the original is empty, the revised content is shown as added. If the revised text is empty, the original content is shown as removed.
What do the added and removed counts measure?
They measure comparison units for your selected mode. In word mode, punctuation and whitespace are also units. These figures are not a percentage similarity score.
Why is a large section highlighted?
Line mode marks complete lines. Large comparisons may also use the labelled block overview, which marks the differing middle sections without finding all internal matches.
Does the comparison change my inputs?
No. Comparing and showing whitespace markers do not modify your inputs. Swap texts exchanges them, and Clear both removes them.
Is the downloaded report a patch file?
No. It is a readable UTF-8 TXT report containing the selected mode, counts and both full texts. It is not a unified diff or an executable patch.