Palindrome Checker

A palindrome is a word, phrase or number that reads the same from left to right and right to left. Examples: "Anna", "racecar", "Was it a car or a cat I saw?". The tool ignores spaces, punctuation and capitalization for the check.

Some famous palindromes: "A man, a plan, a canal: Panama", "Never odd or even", "Was it a car or a cat I saw?", "Madam, I'm Adam". In English they are fun wordplays that challenge writers and logicians alike.

The tool searches for the longest string contained in the input that is itself a palindrome. This is a classic algorithmic problem (Longest Palindromic Substring), solvable in O(n²) with the "expand around center" approach.

A sequence that reads the same in both directions. For phrases the usual convention is to ignore spaces, punctuation and capital letters, which is what makes "A man, a plan, a canal: Panama" count as one.

Capitals are ignored, so a letter matches whatever its case. Accented letters are compared as they are written, because stripping the accent would turn words into palindromes that are not.

It finds the longest stretch inside a longer text that reads the same both ways. It is the classic exercise behind the Manacher algorithm, and a quick way to check a text for hidden symmetry.

Yes, and not because we promise it: this tool runs entirely inside your browser. What you type or upload never leaves your device, so it never reaches a server of ours and there is nothing we could keep, read or lose. You can check it yourself: open the page, disconnect from the internet, and the tool keeps working.

No. There is no database behind this tool: we do not store your files, your text or your results. When you close the tab nothing is left — not here with us, because it never arrived, and not anywhere else.

We do not profile you: there is no account to create, we never ask for your email to use a tool, and we keep no profile of what you do. We are an Italian company and we work under the GDPR and the other European rules, with the privacy notice and the consent request in plain sight. One thing we say in full rather than hiding it behind a slogan: the ads on the page are Google's, and Google may use cookies to personalise them. You decide from the consent banner: if you say no the ads stay, but they are not personalised, and the tool works exactly the same.

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