If you traveled through Europe before 2002, you probably had a lot of fun juggling the different currencies and their crazy exchange rates. You could spend 20 francs on a coffee in Paris and then in Italy it would cost 5000 lira – a bit confusing. But today, you’ll pay for that coffee in Italy and in France with the same bill: the euro.

Even though it’s called the euro after (you guessed it) Europe, its name is a little misleading. There are 45 countries in Europe but only 27 of them have joined the European Union. Out of those 27, only 16 use the euro as their official currency. That’s means only about 1/3 of Europe actually uses the euro! Why so few though?

There are several reasons why:

1. You have to be a member of the European Union to adopt the euro as your currency. There are 18 countries who don’t belong, including Switzerland (which geographically is the center of Europe).
2. You must follow strict financial guidelines to be allowed to have the euro; some countries (like Poland) have yet to meet them.
3. Lastly, you have to want it. Some countries like Britain, Denmark, and Sweden don’t want the euro as their official currency. (If Mexico wanted us to jointly adopt the same currency, we probably would say no as well because of the effect Mexico’s weaker economy would have on our own.)

As Europe continues to loosen the national borders that divide it, the Euro will continue to be adopted by more and more countries. Probably soon, you won’t remember what it was like to carry 20 different currencies in your pocket while visiting only one continent.