Text Compare
Paste two texts and instantly see what was added, what was removed and what stayed the same – including a percentage similarity score.
How to use the tool
Paste the original text into the left field and the new version into the right one. The result appears as a single merged text: green, underlined parts were added, red, struck-through parts were removed, and the rest is unchanged. The "Swap texts" button swaps the contents of both fields, and "Clear" empties both at once.
Pick the comparison mode to match your text. "Lines" works best for code, configuration files or lists, where what matters is which whole lines were added or disappeared. "Words" is best for ordinary text – contracts, emails, articles – because it shows changes at the word level without the noise of minor typos. "Characters" is useful for short strings, or whenever even a single changed letter matters.
The whole comparison runs directly in your browser – the texts are never sent anywhere or stored. The limit is 100,000 characters per field (20,000 in "characters" mode, to protect performance); going over it shows a warning and the comparison isn't run.
Frequently asked questions
How is the similarity percentage calculated?
Using the formula 2 × number of matching units / (length of text A + length of text B), where the unit is lines, words or characters depending on the selected mode. Two identical texts give 100%; completely different texts approach 0%.
Are the texts sent to a server?
No. The whole comparison runs in JavaScript directly in your browser, the texts are never sent anywhere, and nothing is stored once you close the page.
What is the text length limit?
100,000 characters per field in "lines" and "words" mode, and 20,000 characters in "characters" mode – this protects browser performance for the more demanding character-by-character calculation.
How do the comparison modes differ?
"Lines" compares whole lines at once (good for code and lists), "words" splits the text into words (good for ordinary text), and "characters" compares every character individually (good for short strings or spotting typos).
Can the tool compare files or highlight code syntax?
Not in this version – texts are only pasted directly into the fields, file uploads aren't supported, and the result doesn't highlight programming-language syntax, only the differences between versions.
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Last updated: 17 July 2026