Gross Domestic Product — GDP — may have its limits. But it's a useful, broad measure for looking at national economies. It's basically the total dollar value of all of the goods and services a country produces in a year.
Here are all the countries with GDP of over $100 billion:
Having a very large GDP means a country is an important economic player in the world. But it doesn't necessarily mean the country's citizens are rich.
A better measure for looking at the wealth or poverty of a nation's citizens is GDP per capita (adjusted for the fact that $1 buys more in some countries than in others).
Here are all the countries in the world with GDP per capita over $15,000 a year:
Perhaps the most striking difference between the two graphs is China, which has the second biggest economy in the world but is still very poor. China, which has a GDP per capita of $7,599, doesn't even show up on the second graphic.
It's also worth noting that GDP per capita is just an average. So a country with a high level of inequality may have a relatively high GDP per capita, but many poor people.
Update: The World Bank does not list Taiwan as a separate country. Thanks to one of our readers for pointing it out.
Correction: A previous version of the GDP per capita graphic shaded Trinidad and Tobago in red. The bubble should have been dark blue.