According to historians who studied Soviet archives before and after the fall of the Soviet Union, Joseph Stalin likely killed between six million and 20 million people. However, given the widespread and often unrecorded deaths of the Stalin years, it’s certainly possible that that number is even higher.

Cruel efforts under Stalin to impose collectivism and tamp down Ukrainian nationalism left an estimated 3.9 million dead.

He dragged his country toward industrialization at any cost and massacred his enemies — and perceived enemies — causing the deaths of an estimated 20 million people.

There’s little doubt that Stalin’s rule—his forced industrialization, his famine-causing collectivization, his paranoid purges—killed, according to many estimates, between 10 and 20 million people, and he did most probably die of natural causes (see below), so the basic point still stands, but it isn’t strictly true to say he died peacefully, or that his death was unaffected by the brutality of his policies.

Before the dissolution of the Soviet Union and the archival revelations, some historians estimated that the numbers killed by Stalin's regime were 20 million or higher. After the Soviet Union dissolved, evidence from the Soviet archives was declassified and researchers were allowed to study it.