How palindrome detection works
Palindrome checker normalises the input before comparing. Letters are folded to lowercase, digits are kept as-is, and every other character (spaces, punctuation, accents, emoji) is stripped via the regex [^a-z0-9]. The cleaned string is then reversed and compared to itself. If the two are equal, the input is a palindrome.
Output reports a verdict line plus the forward and backward forms of the cleaned string, so you can see exactly what was tested. A man, a plan, a canal: Panama reduces to amanaplanacanalpanama, which is its own reverse, so the verdict is positive. Hello world reduces to helloworld, which reverses to dlrowolleh, so it is rejected.
Switch on the Per Line toggle in the action bar to test each line of input as its own candidate. That mode is handy for vetting a list of words or names. With per-line mode off, the entire input is treated as one phrase.
How to use palindrome checker
- 1Type or paste a word, phrase, or sentence into the input panel.
- 2The verdict appears in the output panel as you type, with the cleaned forward and backward forms.
- 3Toggle Per Line in the action bar to check each line separately.
- 4Click Copy to copy the verdict block, or Download to save it.
- 5No
---separator is needed; this is the only single-input tool in the comparison hub.
Keyboard shortcuts
Drive TextResult without touching the mouse.
| Shortcut | Action |
|---|---|
| Ctrl F | Open the find & replace panel inside the input Plus |
| Ctrl Z | Undo the last input change |
| Ctrl Shift Z | Redo |
| Ctrl Shift Enter | Toggle fullscreen focus on the editor Plus |
| Esc | Close find & replace, or exit fullscreen |
| Ctrl K | Open the command palette to jump to any tool Plus |
| Ctrl S | Save current workflow draft Plus |
| Ctrl P | Run a saved workflow Plus |
How the check is computed
Letters and digits only
Before reversing, the input is lowercased and stripped to a-z and 0-9 via the regex [^a-z0-9]. Spaces, punctuation, accented characters, and emoji are dropped from the comparison.
Case folded to lowercase
Racecar and racecar are treated as the same input. Folding happens before the strip step.
Per Line mode
With the Per Line toggle on, each non-empty line is checked as its own candidate, one verdict per line. With it off (the default), the whole input is treated as one phrase.
Forward and backward both shown
For non-palindromes the output includes Forward and Backward lines so you can see the cleaned string and its reverse. Useful for spotting near-misses caused by a single different letter.
Single-input tool
Palindrome checker is the only comparison-hub tool that does not use a --- separator. Paste one phrase, get one verdict.
Worked example
Stripped to amanaplanacanalpanama, which reverses to itself. Try the classic Was it a car or a cat I saw next, or flip Per Line on to test a list.
A man, a plan, a canal: Panama
"A man, a plan, a canal: Panama" is a palindrome.
Settings reference
| Setting / behaviour | Effect on output |
|---|---|
| Input | Single text only. No --- separator (unlike other comparison tools). |
| Case folding | Lowercased before the strip step. |
| Allowed characters | a-z and 0-9; everything else is removed. |
| Per Line | Default off. When on, each non-empty line is checked individually. |
| Empty input | Returns a prompt to enter a word or phrase. |
| Output (palindrome) | Single verdict line with the original phrase quoted. |
| Output (not) | Verdict plus Forward and Backward lines. |
FAQ
Does it ignore spaces and punctuation?
a-z and 0-9 via [^a-z0-9]. So A man, a plan, a canal: Panama is recognised as a palindrome despite the commas and the colon.How do I test multiple candidates at once?
Why is "noon" reported but accented forms might not be?
é are removed before reversing. To treat é as a palindromic letter you would need to fold accents to ASCII first.