Knowledgebase
How to add and manage currencies in Magento
In Magento you can allow customers to view the prices of the products in your shop in different currencies. To add and remove the currencies that customers can select, log in to the admin panel of your Magento and go to System>Configuration>Currency Setup button in the General section on the left>Currency Options panel on the right. The Currency Options panel has a setting called Allowed Currencies from which you can choose which currencies customers can select on the frontend. Press and hold the Ctrl button on your keyboard and use the left mouse button to mark/unmark currencies in the list.
From the Default Display Currency drop-down menu you can select the default currency from one of the allowed ones. This is the currency that's displayed on the frontend when a customer visits your site. From the Base Currency drop-down menu you can select the base currency for payment transaction. This is also the currency which is used for specifying the price when adding/editing products in the admin panel. After you configure the currency options don't forget to click on the Save Config button.
You also have to configure the currency rates. To do this go to System>Manage Currency>Rates. On the page that opens you'll see a text field for each of the allowed currencies. In these fields you can type the currency rates in relation to the base currency. A faster solution is just to click on the Import button in the upper right corner. In this way all currency rates will be updated; the most recent rates will be imported from Webservicex. Then click on the Save Currency Rates button. If you want to change the currency symbols, you can do that from System>Manage Currency>Symbols.
When it comes to currency rates you can also update them automatically so that you don't have to go each time to System>Manage Currency>Rates and click on the Import button. To update currency rates automatically go to System>Configuration>Currency Setup>Scheduled Import Settings panel and set the Enabled drop-down menu to Yes. If you want to, you can also change the other settings displayed by this panel. Then you need to add a cron job. You can do that from the Cron Jobs section of the Pixie control panel. Assuming that the root Magento directory on your Magento hosting account is public_html you need to add a command that looks like this when adding the cron job: php -f /home/username/public_html/cron.php (replace username with your real username). To make this automatic way of updating currency rates work you may also need to go to your Magento admin panel and edit the settings in System>Configuration>System button on the left>Cron (Scheduled Tasks) panel. For example, you may need to increase the value for the option Missed If Not Run Within.
For screenshots and some more details you can also read the tutorial on managing currencies in Magento.