PHP Currency Regular Expression

Question

Hi All

I am trying to find a piece of regex to match a currency value.

I would like to match only numbers and 1 decimal point ie

Allowed

• 10
• 100
• 100.00

Not Allowed

• Alpha Characters
• 100,00
• +/- 100

I have search and tried quite a few without any luck.

Hope you can advise

Answer 1

Try this regular expression:

^(?:[1-9]\d+|\d)(?:\.\d\d)?$

Answer 2

You might want to consider other alternatives to using a regex.

For example, there's the NumberFormatter class, which provides flexible number and currency parsing and formatting, with build in internationalisation support.

It's built into PHP 5.3 and later, and is available as an extension on earlier versions of PHP 5.

Answer 3

if (preg_match('/^[0-9]+(?:\.[0-9]+)?$/im', $subject))
{
    # Successful match
}
else
{
    # Match attempt failed
}

Side note : If you want to restrict how many decimal places you want, you can do something like this :

/^[0-9]+(?:\.[0-9]{1,3})?$/im

So

100.000

will match, whereas

100.0001

wont.

If you need any further help, post a comment.

PS If you can, use the number formatter posted above. Native functions are always better (and faster), otherwise this solution will serve you well.