Text diff

How to use it

1. Paste the old version into “Original text” and the new one into “Changed text” — the diff appears as you type, there is no button to press.
2. If the page is all red and green because of trailing spaces or case, switch on the matching rule above. Chinese pages additionally offer full-width/half-width folding.
3. Use “Copy diff” to take the result away as a unified diff (+ / −) and paste it into a ticket, an email or an editor.

Example

【Original】
Meeting: 10:00
Room: 3F
Owner: Li Ming

【Changed】
Meeting: 10:30
Room: 3F
Owner: Li Ming, Wang Fang

-Meeting: 10:00
+Meeting: 10:30
 Room: 3F
-Owner: Li Ming
+Owner: Li Ming, Wang Fang
(+2 −2, 1 unchanged line)

The 【Original】/【Changed】 lines are example headings; in real use the two texts go into the two input boxes. Nothing is ignored by default, so both changed lines are marked in full, while “Room: 3F” is identical and shown as a normal line.

Rules, limits and known issues

• The unit of comparison is a line: change one word inside a line and the whole line is marked as removed + added. There is no character-level highlight inside a line.
• A replacement is shown the way git diff shows it: the removed old line first, then the added new line.
• “Ignore edge whitespace” only trims horizontal whitespace at both ends of a line (space, tab, U+00A0, U+3000); spaces inside a line are never collapsed.
• “Ignore full-width/half-width” only affects matching: “，” equals “,”, “（）” equals “()” and a full-width space equals a normal space — the result still shows your original text.
• With “Ignore blank lines” on, lines that are empty or contain only whitespace are neither compared nor displayed; the visible line numbers still refer to the original text.
• When only one side ends with a line break, the diff shows one added or removed empty line — that is a real difference and is never hidden for you.
• No Unicode normalization: “é” (one code point) differs from “e” plus a combining accent (two code points). Block moves are not detected: moving a paragraph from the top to the bottom shows as one removal plus one addition.
• Above 200,000 characters combined the result updates about 0.6 s after you stop typing; above 3,000 lines or with very large differences the middle part is compared as one block and a note is shown above the result.
• No file upload, no Word/PDF parsing, no side-by-side view, no history and no share links — nothing is uploaded and nothing is stored.

Related text tools

What people usually need next, once the differences are found.