[regex] HTML5 Form Input Pattern Currency Format

Using HTML5 I have an input field that should validate against a dollar amount entered. Currently I have the following markup:

<input type="number" pattern="(\d{3})([\.])(\d{2})">

This works great for an amount that is greater than 100.00 and less than 1,000.00. I am trying to write the pattern (regex) to accept different dollar amounts. Maybe upwards of 100,000.00. Is this possible?

The best we could come up with is this:

^\\$?(([1-9](\\d*|\\d{0,2}(,\\d{3})*))|0)(\\.\\d{1,2})?$

I realize it might seem too much, but as far as I can test it matches anything that a human eye would accept as valid currency value and weeds out everything else.

It matches these:

1 => true
1.00 => true
$1 => true
$1000 => true
0.1 => true
1,000.00 => true
$1,000,000 => true
5678 => true

And weeds out these:

1.001 => false
02.0 => false
22,42 => false
001 => false
192.168.1.2 => false
, => false
.55 => false
2000,000 => false

I'm wrote this price pattern without zero price.

(0\.((0[1-9]{1})|([1-9]{1}([0-9]{1})?)))|(([1-9]+[0-9]*)(\.([0-9]{1,2}))?)

Valid For:

• 1.00
• 1
• 1.5
• 0.10
• 0.1
• 0.01
• 2500.00

Invalid For:

• 0
• 0.00
• 0.0
• 2500.
• 2500.0000

Check my code online: http://regexr.com/3binj

I like to give the users a bit of flexibility and trust, that they will get the format right, but I do want to enforce only digits and two decimals for currency

^[$\-\s]*[\d\,]*?([\.]\d{0,2})?\s*$

Takes care of:

$ 1.
-$ 1.00
$ -1.0
.1
.10
-$ 1,000,000.0

Of course it will also match:

$$--$1,92,9,29.1 => anyway after cleanup => -192,929.10

Another answer for this would be

^((\d+)|(\d{1,3})(\,\d{3}|)*)(\.\d{2}|)$

This will match a string of:

• one or more numbers with out the decimal place (\d+)
• any number of commas each of which must be followed by 3 numbers and have upto 3 numbers before it (\d{1,3})(\,\d{3}|)*

Each or which can have a decimal place which must be followed by 2 numbers (.\d{2}|)

How about :

^\d+\.\d{2}$

This matches one or more digits, a dot and 2 digits after the dot.

To match also comma as thousands delimiter :

^\d+(?:,\d{3})*\.\d{2}$

Use this pattern "^\d*(\.\d{2}$)?"