Learn how to use PHP regex to validate float numbers

By admin|PHP

If you want only input 0-9 and only once “.” then you can use following regex.

/^-?(?:\d+|\d*\.\d+)$/

This matches normal floats e.g. 3.14, shorthands for decimal part only e.g. .5 and integers e.g. 9 as well as negative numbers.

echo preg_match('/^-?(?:\d+|\d*\.\d+)$/', '123.12'); // return 1
echo preg_match('/^-?(?:\d+|\d*\.\d+)$/', '123.12.2'); // return 0