How many people were enslaved in the Atlantic trade?

The answer

Scholarly estimates run into the millions and vary because records are incomplete and researchers count different things. The Trans-Atlantic Slave Trade Database, as described by the National Endowment for the Humanities, records about 12.5 million people embarked and about 10.7 million who survived the crossing between 1526 and 1866. Responsible teaching quotes a range, names the source and what it counts, and avoids repeating a single number as certain.