If you currently have your billing set up or a specific currency, Google will also track your conversions in that same currency, regardless of what currency was actually used for the conversion.  Google has announced that they are changing currencies for conversions to now support multiple currencies for conversion purposes in Google AdWords accounts.

Let’s say you’re an online retailer based in the UK, promoting your products from an AdWords account billed in pounds (£). You accept payments in three currencies on your site–pounds, euros and dollars. Previously, when a customer paid for something in euros or dollars, you had to convert the payment into pounds in order to reconcile all the currencies into a single revenue amount for your business.

Now, AdWords will convert the payment currency from euros and dollars to pounds, so you don’t have to. When you have both your costs and sales all in one currency, you can calculate a more meaningful return on investment. Learn how to add currency to your conversions: http://goo.gl/UdrDbW

You do need to use specific currency codes in order for Google to track the currencies correctly.  If the currency code is entered incorrectly, it will default to the account’s current currency.  You can find all the currency codes here.

Google converts the currency based on the current  exchange rate.

Your MCC account’s default currency is British Pounds. You created a conversion action you’ve valued at £10. Someone clicks an ad served by a managed account with a default currency of Euros and completes a conversion action. The current exchange rate is £1 = €1.19. In the managed account, we’ll show a conversion value of €11.93. The conversion value will still be shown as £10 in the MCC account.

The chance is currently live on all Google AdWords accounts.