Electricity in Italy
Electricity in Italy is 220 volts, 50 cycles alternating current (AC). For comparison, in the United States it is 110 volts, 60 cycle AC current.
If you plan on using your own 110-volt appliances, you will need a voltage converter, unless your appliance is designed to also work with 220 volts electricity (dual voltage). For example, most laptops and some electric shavers are designed to work both at 110 and 220 volts. Plugging in an appliance that is not designed to run on 220 volts electricity without using voltage converter will most likely kill it.
If you plug an appliance that needs more power than a power converter can handle, the converter might get overloaded. This can cause it to overheat, shut down, or even get damaged. In some cases, it could also trip a fuse or cause a fire. It's important to use a converter that can handle the power requirements of the appliance. For hassle-free travel, it might be easier to buy a dual voltage appliance rather than dealing with the inconvenience of finding the right power converter. Dual voltage devices, such as hair dryers, electric razors, curling irons, and phone chargers, automatically adjust to different power standards, making them a more convenient and reliable option for international trips.
Voltage converters might not be always easy to find in Italy, and definitely, you don't want to bother with looking for one while you should be sightseeing or relaxing. If you think you will need one, it is a good idea to get it before you leave home.
Regardless of voltage, if your appliance has flat prongs, you will need a plug adapter: Italian sockets are designed to accept round prongs. Do get one before you leave!
As a matter of fact, Italian plugs can be of two different sizes. Some socket will take in the plugs with large prongs only, some other will take in the ones with small prongs (more common for small appliances; large prongs are used for demanding appliances such as refrigerators and washing machines). And then there are sockets, like the one pictured at the top of this page, designed to take in any kind of plug.
Well, almost any kind... nowadays more and more demanding Italian appliances have "Shuko", or German-style plugs, which need to be plugged in an a special socket, or require a special converter. They are quickly replacing the "large prongs" appliances. However, you don't have to worry about this. It is really a detail. German-style sockets (which are not as common as German-style plugs) will allow you to plug in your small-prong plug adapter just like any regular small-prong socket.