Palindrome Checker
Check if a word, phrase or sentence is a palindrome. Finds palindromic words and the longest palindromic substring.
amanaplanacanalpanamaamanaplanacanalpanama(21 chars)What is Palindrome Checker?
A palindrome checker determines whether a word, phrase, number, or sentence reads identically forwards and backwards. Classic word palindromes include "racecar", "level", and "madam". Phrase palindromes, which ignore spaces and punctuation, include "A man, a plan, a canal: Panama" and "Never odd or even". Number palindromes such as 12321 and 11011 also appear in mathematics and date formats.
Palindromes have fascinated people for thousands of years. Ancient Greek and Latin writers crafted palindromic inscriptions. In mathematics, palindromic primes and palindromic dates carry special significance. In genetics, DNA palindromes are sequences where the complement strand reads the same and are the recognition sites for restriction enzymes used in gene editing.
This checker handles all common variants. It checks strict palindromes (exact character match in reverse), case-insensitive palindromes, and phrase palindromes (ignoring spaces and punctuation). You can also check number palindromes and discover near-palindromes — words that are one character substitution away from being a palindrome.
The tool also includes a batch mode where you can paste a paragraph or word list and it highlights every palindromic word found within the text. Whether you are playing word games, writing creative content, exploring mathematical curiosities, or just satisfying your curiosity, the checker gives instant, clear results.
How to Use Palindrome Checker
- Type or paste your text
Enter a word, phrase, sentence, or number into the input field. The checker works with any length of text.
- Choose check mode
Select strict mode, case-insensitive mode, or phrase mode (ignores spaces and punctuation).
- See the result instantly
The checker highlights whether your input is a palindrome and shows the reversed text for comparison.
- Find palindromes in a list
Paste a word list or paragraph into batch mode to highlight every palindromic word in the text.
Key Benefits
Results appear as you type — no need to click a check button.
Strict, case-insensitive, and phrase modes (ignoring spaces and punctuation) cover all common palindrome definitions.
Paste a block of text and highlight every palindromic word in one pass — great for word game prep.
Your text never leaves the browser. No input is stored or processed on a server.
Frequently Asked Questions
A phrase palindrome reads the same forwards and backwards when you ignore spaces, punctuation, and capitalisation. "A man, a plan, a canal: Panama" is a classic example — stripping non-letters gives "amanaplanacanalpanama", which is the same reversed.
Yes. Number palindromes like 12321 or 1001 are detected in the same way as word palindromes — the digit sequence must read identically in both directions.
A palindromic prime is a number that is both a prime (divisible only by 1 and itself) and a palindrome. Examples include 11, 101, 131, and 313. They are rare and of interest in recreational mathematics.
Yes. The checker works on any Unicode text, so words and phrases in French, Spanish, Arabic, and other scripts are all handled correctly, as long as the reversal logic applies to the character sequence.