When you travel internationally, you should always throw a plug adaptor into your bag. This graphic is a quick reference to common plug types and the countries in which they're used. This way you'll know which type of adaptor to pack for your trip.
In the below infographic, you can each type of plug, the countries the countries they're used in, and which types are compatible, so you know if you need a single adaptor or not. The only thing the graphic doesn't account for is voltage, which you should still take time to check. Just because you have an adaptor won't mean you can use the plug with your devices if they use a different voltage than your home country.
The Ultimate Guide to Travel Plugs [Citybase Apartments]