Palindrome Checker Text
Check whether a word or phrase reads the same backwards.
Palindrome Checker is a free online tool that check whether a word or phrase reads the same backwards. It runs entirely in your web browser using plain JavaScript, so files are processed on your own device and never uploaded to a server. There is no sign-up, no file size limit imposed by the site, no watermark and no paid tier.
- Price
- Free — no account, no quota, no watermark
- Category
- Text
- Where it runs
- In your browser, on your device
- Files uploaded
- None
- Technology
- plain JavaScript
- Settings
- None — it just works
- Works offline
- Yes, after the first visit
About Palindrome Checker
Whether a phrase is a palindrome depends entirely on how you normalize it, which is the interesting part. "A man, a plan, a canal: Panama" is a palindrome only if you discard punctuation, spaces and case. Each of those is a separate option here, because the answer legitimately changes: strictly, with punctuation intact, that phrase is not one.
How to use it
- Paste the text you want to run through palindrome checker.
- There is nothing to configure — the result updates as you type.
Under the hood
| Runs on | plain JavaScript — runs the whole thing |
Questions
What is the longest palindromic word in English?
"Tattarrattat", coined by James Joyce in Ulysses, at twelve letters. In common use, "redivider" at nine is the usual answer.
Are numbers checked the same way?
Yes — 12321 is a palindrome. Palindromic numbers turn up in the Lychrel problem, which is unsolved: nobody has proved whether 196 ever reaches a palindrome under repeated reverse-and-add.