Easy Currencies is a desktop currency calculator for Mac OS X and Windows. The application consists of two windows, at least on Mac. One of them shows a list of currency rate pairs, which by default consists of 17 pairs. You can add more pairs from the settings menu. Next to each pair is the currency rate for that pair. For example, at the time of this review the exchange rate between Euros and U.S. Dollars was of 1.4136. The second window is where the actual calculations are made. There, you can choose from a drop-down menu the currency that you want to calculate. And it will display calculations for 12 different currencies, including Gold. For example, if you select Argentine Pesos from the drop down menu and type 100, the application will calculate how many USD, Euros, GBP, etc you can buy with $100 Argentine Pesos.
The exchange rates are automatically updated when you start the application, and you can update them manually by clicking on the "Refresh" button. Easy Currencies seemed to have accurate rates. In the case of Argentine Pesos, it calculated an average between selling and buying prices.
All in all, although you can probably get this functionality for free with other apps, Easy Currencies works very well. The only thing that I did not like is that the main window wasn't set to stay on top of other apps and I had to frequently click on its dock icon to bring it up.