Palindrome Number Checker Calculator

Work out palindrome number checker instantly with clear inputs, formula shown and shareable results.

About Palindrome Number Checker Calculator

A palindromic number reads the same forwards and backwards. If it is not already one, repeatedly adding the reverse often produces a palindrome, usually within a handful of steps.

Formula

Palindrome test

v is palindromic if its digit string equals its reverse

Worked example

With the default values below, Palindrome Number Checker Calculator returns Result of 12321 is a palindrome. Change any input above and every figure here is recalculated in your browser.

Inputs used

Number to test: 12,321
Reverse-and-add steps to tryaccepts 1–30: 5

Results

Result: 12321 is a palindrome
Reversed number: 12,321
Palindrome reached by reverse-and-add: 12,321
Steps needed: 0

Step by step

1Values used
2Palindrome test
3Result= 12321 is a palindrome
4Reversed number= 12,321
5Palindrome reached by reverse-and-add= 12,321
6Steps needed= 0

Assumptions and limits

The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to whole numbers, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Is 12321 a palindrome?

Yes, it reads identically in both directions.

Does reverse-and-add always terminate?

Not provably. 196 has been tested for hundreds of millions of digits without reaching a palindrome.