Free Palindrome Checker Online

"A man, a plan, a canal: Panama." Strip the punctuation and spaces and that sentence reads the same backward as forward — the perfect palindrome, attributed to Leigh Mercer in 1948 and still the favourite example in every linguistics class. Our free online Palindrome Checker tests any word, phrase, or sentence against the same definition. Type or paste your text and the tool tells you immediately whether it qualifies, with toggles to control how strict the check should be: ignore case (so "Madam" matches "madam"), ignore spaces (so multi-word phrases work), and ignore punctuation (so the Panama example passes). It also shows the reversed version of your input alongside the original, which is helpful when something almost matches and you want to see exactly where it diverges. Beyond simple yes/no checking, the tool highlights the longest palindromic substring inside your text — useful for word puzzles, programming interview questions, and just satisfying curiosity. Real-world uses: solving crossword and word puzzle challenges, double-checking a creative writing piece that depends on palindromes, learning about palindromes for a school assignment, or testing inputs for the classic computer-science interview question "find the longest palindrome substring". After checking, the [Anagram Checker](/tools/anagram-checker) handles the related "letters in any order" case, the [Word Count](/tools/word-count) tool counts characters and words in your text, and the [ASCII Converter](/tools/ascii-converter) is the right tool for character-level inspection.