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About Palindrome Checker Online
This tool checks whether a piece of text is a palindrome — reads the same forwards and backwards. "racecar" and "A man, a plan, a canal: Panama" are both palindromes; "hello" is not.
Standard palindrome rules ignore spaces, punctuation, and letter case. So "A Santa at NASA" qualifies as a palindrome despite mixed casing and spaces. The tool applies these rules automatically and also offers a strict mode that requires exact character matching.
Useful for word games, puzzles, programming interview prep, linguistic exploration, and just for fun. It also highlights the longest palindromic substring within longer texts, which surfaces hidden palindromes you might miss.
How to use this tool
How to test if a string is a palindrome
Paste any word or phrase
Type or paste text into the Text field. Punctuation, spaces, and letter case do not affect the verdict.
Understand the normalisation
Only [a-z0-9] survive: the tool lowercases the input, strips everything else, then compares with its reverse. "A man, a plan, a canal: Panama" becomes "amanaplanacanalpanama".
Press Run
The result returns isPalindrome (true/false) and the normalised string so you can see exactly what was compared.
Watch the edge cases
Empty strings and single characters return true. Non-Latin scripts (Arabic, CJK) collapse to empty after normalisation, so they also return true.