If you’re planning on bringing a phone, tablet, computer, hairdryer, electric razor, or other device that needs electricity, this section is worth a read. Europe’s electrical system is different from the U.S. in two ways: the voltage of the current and the shape of the plug.
Voltage: American appliances run on 110 volts, while European appliances use 220 volts. Most newer travel accessories and electronic devices (such as iPhones and Android phones) are “dual voltage,” which means they can be charged using both American and European current. If you see a range of voltages printed on the item or its plug (such as “110–220”) they’re OK to use in Europe.
Adapters: U.S. plugs have 2 flat prongs (not grounded) or 2 flat prongs + 1 round prong (grounded). Continental European outlets take two round prongs, and British & Irish outlets take three flat prongs arranged in a rectangle. A U.S. plug will not fit into either of these without the help of an adaptor.
If all of your devices can take 110 or 220 volts, then all you need is an adaptor. However, if you have devices that only take 110 volts, then you need to bring a combination adaptor/converter. Magellans a good place to find both items.