Last updated 26 August 2026
Why the cleanup matters
Famous phrase-palindromes like "A man, a plan, a canal: Panama" only work once spaces, punctuation and capital letters are stripped away — checked as raw text they'd fail immediately. This tool cleans the input the same way before comparing it against its own reverse, so both single words and full phrases get checked fairly.
What counts as a palindrome here
Strictly read, a palindrome is identical character for character in both directions. By that rule almost no real sentence qualifies, because spaces and punctuation fall in the wrong places. The usual convention — and the one used here — is to ignore case, spaces and punctuation, so "A man, a plan, a canal: Panama" comes back as a palindrome even though the raw characters do not mirror.
That convention is why results differ between tools. A checker that compares raw text will reject the same sentence this one accepts, and neither is wrong; they are answering slightly different questions.
Numbers work the same way, and so do single words like level or rotator. Accented letters are compared as written, so é and e are treated as different characters — worth knowing if you are testing text in a language that uses them.
Common questions
Why does it ignore spaces and capitalization?
Because phrase-level palindromes like 'A man, a plan, a canal: Panama' only work if you ignore spaces, punctuation and case — checking the raw text character-for-character would say it isn't one, which misses the point.
What's the simplest example of a palindrome?
Single words like 'level', 'racecar', and 'noon' are the clearest examples — spelled identically read in either direction, no cleanup needed.
Do numbers count as palindromes too?
Yes — a number like 12321 is checked the same way as text, since it reads identically in both directions.