How many countries are there in the world? While this might seem to be a simple question, the answer is quite complicated.
The problem is that different organizations have different stances on exactly what it takes to qualify as a country. Depending on the source, the number of countries can vary quite considerably, and there is no universal agreement on the total.
That said, the United Nations is generally regarded as the de facto authority on nationhood. Currently, the U.N. recognizes 193 countries as member states. It also recognizes two "observers states", the Holy See/Vatican City and Palestine, which are self-ruling territories but not full-fledged countries.
However, even the U.N. list is not free of controversy. The U.N. does not currently acknowledge the self-governed territory of Taiwan (Republic of China), which was a member of the U.N. from 1945 to 1971, but is now considered a territory of mainland China. Similarly, as of 2020, roughly half of U.N. members still considered Kosovo to be part of Serbia rather than its own nation.
By comparison, Britannica's list of countries grants full nation-hood rights to Vatican City, Taiwan, and Kosovo for a total of 196 countries. Then there's Wikipedia's list of sovereign states, which mirrors the U.N.'s list of 193 countries and two observer states, then adds eleven sovereign states, including Taiwan, Kosovo, Northern Cyprus, Cook Islands, and more for a total of 206.
Perhaps the most puzzling non-country is Greenland, a massive island between the north Atlantic and Arctic oceans, which certainly looks like it ought to be its own country—just like its tiny neighbor, Iceland. However, Greenland is not a U.N. member country and, while it controls many of its own domestic affairs, it is ultimately controlled by Denmark, a European country even tinier than Iceland, thousands of miles away.
Other sources use a less rigid definition of country and give dependent and disputed territories such as Greenland and the Gaza Strip their own separate listings. This is the reason the United States' CIA Factbook lists 237 countries.
All of this demonstrates that it is not so simple to determine the exact number of countries there are in the world. Moreover, and the constantly changing nature of politics means that issues around sovereignty are unlikely to ever be fully resolved.
For the ultimate list of not just countries, but also territories and regions that have some degree of self-governance but are not universally considered fully-fledged countries, check the table below.