Palindrome checker

Palindrome checker is a free tool that checks whether a word or phrase reads the same backwards and forwards.

How do I use the palindrome checker?

Enter or paste the text you want to test, then read the result.

1. Copy the word, number or phrase exactly as you received it.
2. Paste it into the checker.
3. If the answer is unexpected, inspect capital letters, spaces and punctuation before trying a cleaned version, but only if the checker's verified comparison rules treat them as significant.

Keep the original text while testing a cleaned copy for palindrome comparison. This is particularly useful with spreadsheet data because it prevents accidental changes to names, references or puzzle answers.

What counts as a palindrome?

A palindrome is a sequence that remains the same when its order is reversed. Familiar examples include level, radar and the number 12321.

There are two common ways to assess longer text. An exact comparison treats every character as significant, including spaces and capital letters. A normalised comparison may convert letters to one case and remove spaces or punctuation first. This is why a phrase can count as a conventional palindrome even though its unedited character sequence is not identical in reverse.

The intended rule depends on the task. Use exact comparison for software tests, product codes and identifiers. Ignoring case and punctuation is usually more appropriate for word games, quizzes and editorial copy.

Where does checking palindromes save time?

Palindrome checking saves time when a list or piece of copy contains candidates that would otherwise need to be reversed and compared by hand.

• Check proposed answers before publishing a word puzzle in WordPress.
• Verify answer sets for a palindrome round in Kahoot or Microsoft Forms.
• Review words copied from an Excel or Google Sheets column during puzzle preparation.
• Create expected pass and fail cases for a string-handling exercise stored in GitHub.
• Confirm whether a reference number is symmetrical before adding it to a report or design.

For a long spreadsheet column, a script or spreadsheet formula is more suitable than checking entries individually. If an exported list contains repeated candidates, Duplicate lines remover can reduce the list before each distinct entry is checked.

Worked palindrome examples

These examples state the comparison rule so that the result is unambiguous.

• racecar becomes racecar when reversed, so it is an exact palindrome.
• hello becomes olleh, so it is not a palindrome.
• 12321 remains 12321, so digits can form a palindrome when treated as text.
• Racecar is not an exact case-sensitive match, but it is a palindrome after conversion to lower case.
• A man, a plan, a canal, Panama! becomes amanaplanacanalpanama after removing spaces and punctuation and converting it to lower case. That cleaned sequence is a palindrome.
• été reads identically in reverse, including its accented characters.

How do spaces, punctuation and unusual characters affect the result?

The comparison rules determine how spaces, punctuation and unusual characters affect a palindrome result. A space is a character in an exact comparison, as are apostrophes, hyphens and full stops.

Accented and non-Latin letters can form palindromes, but visually similar characters are not always stored identically. For example, an accented letter may be represented as one Unicode character or as a base letter followed by a combining mark. Emoji can also contain several code points, so reversing them as individual code points may not match what a person sees on screen.

An empty string is considered a palindrome in some mathematical and programming definitions because reversing it changes nothing. Many practical exercises require at least one character instead. The checker determines whether text reads the same in reverse, but it does not establish which definition a competition, coding task or editorial style guide expects.

Frequently asked questions

Is a single letter a palindrome?

Yes. A single letter is unchanged when reversed, so it meets the standard definition. The same applies to any single character, including one digit.

Is 010 a palindrome?

It is a palindrome when treated as the three-character text 010. If software converts it to the number 10 and removes the leading zero, the resulting decimal representation, 10, is not palindromic.

Is a palindrome the same as a semordnilap?

No. A palindrome remains the same when reversed, while a semordnilap produces a different valid word, such as stressed and desserts. The terms describe separate forms of wordplay.

Can a palindrome checker test DNA sequences?

It can identify whether a sequence of letter symbols is identical in reverse. In genetics, however, a reverse complement replaces each nucleotide with its paired base as well as reversing the order, so an ordinary text palindrome check does not perform that biological operation.

Is there a longest palindrome?

No universal longest palindrome exists because characters or palindromic sections can be added indefinitely. A puzzle may impose its own limits, such as requiring a dictionary word, a grammatical sentence or a fixed number of characters.

Before recording a result, note whether case, spaces and punctuation were included. That small detail makes the answer reproducible for anyone checking the same text later.