What Is a Palindrome? Examples and Checker (2026)

A palindrome is a word, number, phrase, or sequence that reads the same forwards and backwards, ignoring spacing and punctuation. The word comes from the Greek palindromos — "running back again." Recognising palindromes is a classic problem in string processing, linguistics, and competitive programming, and the underlying logic appears in DNA sequence analysis and data validation.

Common examples

Single words are the easiest case: racecar, level, civic, and radar are all palindromes. Phrases work too when spaces are stripped: "A man a plan a canal Panama" and "Never odd or even" are well-known examples. Numbers follow the same rule — 121, 1331, and 12321 are numeric palindromes. The table below shows a cross-section across categories.

How to check programmatically

The standard algorithm strips non-alphanumeric characters, lowercases the result, then compares it to its reverse. In most languages this is three lines. The edge cases worth handling: empty strings (technically palindromes), single characters (always palindromes), and Unicode — accented characters like é should be normalised before comparison if you want consistent results across languages. For a phrase checker, decide upfront whether spaces and punctuation count — most definitions exclude them.

Use the Palindrome Checker to test any word, phrase, or number instantly without writing a single line of code.