how long has communism been in existence

Communism has existed in some form for more than 2,000 years, if you count early ideas about shared property in ancient philosophy and early religious communities. If you mean modern communism as a political ideology, it dates mainly to the 1840s, especially Karl Marx and Friedrich Engels’ The Communist Manifesto in 1848.

Simple timeline

• Ancient roots: ideas similar to communism appeared in Plato’s time and in early Christian communal practices.

• Modern theory: the 1840s, when Marx and Engels developed communist doctrine.

• Political movement: communism became a major real-world force after the 1917 Russian Revolution.

Plain answer

So the shortest accurate answer is: communist ideas are very old, but communism as a modern political movement is about 180 years old.