What is the best way to change the currency's precision?

I have a store that uses Euro as the currency, but I want to change the precision from 2 decimal places to 3.

I know that the locale data is stored under /lib/Zend/Locale/Data but is this really the best place to change this sort of information.

  • 1
    I would be concerned about the reliability of changing this. I believe that Magento (unfortunately) has some hardcoded assumptions regarding currency precision. Also, Zend_Locale_Data makes some assumptions about the relative location of the localization XML files :-/
    – benmarks
    Jan 14 '14 at 13:56
  • Yeah the 2 is hard coded in place for Magento :( Jan 14 '14 at 14:00

Ok first of all I saw the event currency_display_options_forming and I thought that this would be so easy, but sadly that was not the case :( You can use this event to change the display of the currency across the whole site but the follow code stops the precision from working in all cases.

Under Mage_Directory_Model_Currency there is a function formatPrecision. Here it checks for the options and if it does not find one for precision it will hard code it to 2!

So the first thing I did as Marius said is to rewrite the Mage_Directory_Model_Currency::format I chose to set it up with xml (great minds think alike)

public function format($price, $options = array(), $includeContainer = true, $addBrackets = false)
    return $this->formatPrecision(
        Mage::getStoreConfig(self::XML_PATH_CURRENCY_ALLOW), // Mage uses '2' here

But that only changes the display. Most of the price displays all call Mage_Core_Model_Store::roundPrice and this again has a hard coded 2, I am starting to think this was a bad idea.

public function roundPrice($price)
    return round($price, 2);

So the obvious thing now is to rewrite the roundPrice function and again use the same xml config value.

public function roundPrice($fPrice)
    return round($fPrice, Mage::getStoreConfig(Sitewards_Currency_Model_Format::XML_PATH_CURRENCY_ALLOW));

Now that covers most of the front-end if you also want to change this in the admin section that would involve changing templates and rewriting at least Mage_Adminhtml_Block_Catalog_Product_Helper_Form_Price

public function getEscapedValue($iIndex=null)
    $fValue = $this->getValue();

    if (!is_numeric($fValue)) {
        return null;

    return number_format($fValue, Mage::getStoreConfig(Sitewards_Currency_Model_Format::XML_PATH_CURRENCY_ALLOW), null, '');

One not on the template front, the one I know about now is catalog/product/edit/price/tier.phtml as again that has <?php echo sprintf('%.2f', $_item['price']) ?>

On one final note the admin grid actually does work with the first event currency_display_options_forming.

I will update this answer the more I find out, but it is still a work in progress.


I think you can override the method Mage_Directory_Model_Currency::format.
Right now it looks like this:

 public function format($price, $options=array(), $includeContainer = true, $addBrackets = false)
    return $this->formatPrecision($price, 2, $options, $includeContainer, $addBrackets);

The second parameter for formatPrecision is the number of decimals. Change it to :

 public function format($price, $options=array(), $includeContainer = true, $addBrackets = false)
    return $this->formatPrecision($price, 3, $options, $includeContainer, $addBrackets);

Or if you want to be "politically correct", to this:

 public function format($price, $options=array(), $includeContainer = true, $addBrackets = false)
    return $this->formatPrecision($price, Mage::getStoreConfig('some/path/here'), $options, $includeContainer, $addBrackets);

and define a config setting that you can change later.

  • Oh Marius I wish it was that easy ;) that is about a third of what I have done so far. Will post the complete (as in how far we have tested) answer soon. Jan 18 '14 at 8:31
  • 1
    @DavidManners I imagined it was not only this, but I thought that a pattial answer is better than no answer.
    – Marius
    Jan 18 '14 at 8:34
  • Yup you are right. I am typing up my slightly less partial answer now also :) Jan 18 '14 at 8:41
  • Please I am new to Magento 2, I need the full solution files.
    – Jsparo30
    May 4 '17 at 11:37

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