Officially there are 30 reigning monarchies in the entire world. There are twelve monarchies in Europe, thirteen in Asia, three in Africa and two in Oceania. Lists often leave out Andorra and Vatican City, which according to their constitution really are monarchies. On the other hand the United Arab Emirates has a president, and is sometimes regarded a republic, but it exists of seven monarchies. Also Samoa is often not counted as it is a mix of a parliamentary republic and a constitutional monarchy. I have tried to present all monarchies here. Any more information is welcome.
Europe
Africa
Asia
Oceania