How Many People Were Taken in the Atlantic Slave Trade?

The most authoritative current reconstruction is the SlaveVoyages Trans-Atlantic Slave Trade Database, developed by an international scholarly team led initially by historians David Eltis, Stephen D. Behrendt, David Richardson and Herbert S. Klein. Its estimates cover 1501–1866: approximately 12.52 million people embarked in Africa, while approximately 10.70 million disembarked across the Atlantic.

The difference—about 1.82 million people, or roughly 14.5% of those embarked—represents estimated deaths during ocean transport. It does not measure deaths before embarkation or after landing. “Taken” can therefore mean at least three different populations: people seized or sold into the Atlantic system; people put aboard ships; or people delivered alive in the Americas. The figure 12.5 million answers the second meaning and is the standard answer to the question.

See the archive’s broader history of enslavement and empire, documented colonial atrocities, and guidance on interpreting historical data.

There was no single Atlantic register. Scholars reconstructed the traffic voyage by voyage from customs accounts, port books, shipping lists, insurance records, merchant correspondence, captains’ logs and court papers. The database’s 2026 interface contains records for more than 36,000 transatlantic voyages conducted from 1514 to 1866; statistical models fill gaps where surviving records identify a voyage but omit embarkation or landing totals.

David Eltis and David Richardson’s Atlas of the Transatlantic Slave Trade (2010) mapped 12.52 million embarkations and 10.70 million arrivals for 1501–1866, drawing on the database then available. Earlier scholarship produced lower totals because archives and voyages remained unidentified.

“The shrieks of the women, and the groans of the dying, rendered the whole a scene of horror almost inconceivable.” — Olaudah Equiano, 1789, The Interesting Narrative of the Life of Olaudah Equiano

Equiano’s account describes the Middle Passage from the captive’s perspective. It cannot establish an Atlantic-wide total, but it records what aggregate shipping data necessarily abstracts: confinement, terror, disease and death.

The estimates are not rival counts of exactly the same evidence. They show how scholarship changed as researchers found more shipping records and adopted voyage-level reconstruction. The broad historical range runs from approximately 9.6 million arrivals in Philip D. Curtin’s 1969 census to 12.52 million embarkations in Eltis and Richardson’s 2010 atlas.

Source	Publication year	Period represented	Estimated population	What it measures
Philip D. Curtin, The Atlantic Slave Trade: A Census	1969	c. 1451–1870	9.57 million	People imported alive across Atlantic destinations
Paul E. Lovejoy, revised synthesis	1982	1450–1900	11.70 million	Exports from Africa in the Atlantic trade
David Eltis and colleagues, CD-ROM database	1999	1519–1867	about 11.06 million	Estimated embarkations using 27,233 voyage records
Eltis and Richardson, Atlas / SlaveVoyages	2010	1501–1866	12.52 million embarked; 10.70 million landed	Reconstructed transatlantic voyages

Curtin’s 1969 figure overturned unsupported claims reaching 15 million or more, but later research showed that his 9.57 million arrivals understated traffic in several regions. Lovejoy’s 1982 estimate of 11.70 million exports and the database projects initiated in the 1990s narrowed uncertainty by linking records across European, African and American archives.

The defensible headline is not “exactly 12,521,337 victims.” It is about 12.5 million embarked between 1501 and 1866, based on the strongest voyage-level reconstruction, with roughly 10.7 million recorded or estimated as landing alive.

Serious scholarly disagreement concerns definitions, missing evidence and statistical reconstruction—not whether mass forced transportation occurred. Some historians prefer a range of approximately 12 million to 12.8 million embarkations for 1501–1866, rather than treating the SlaveVoyages estimate of 12.52 million as an exact count. Records are weakest for illicit voyages after abolition laws, small early voyages, and traffic to poorly documented ports.

The British Parliament prohibited British participation through the Slave Trade Act 1807, effective 1 May 1807; the United States barred legal importation from 1 January 1808. Neither law ended the traffic. Brazil’s Eusébio de Queirós Law of 4 September 1850 was followed by stronger suppression, while the last known transatlantic slave voyage in the database occurred in 1866. Smuggling encouraged false manifests, concealed destinations and destruction of evidence.

Higher totals often answer a different question. If “taken” includes those killed in capture, wars stimulated by slave demand, marches, coastal prisons and raids, the toll necessarily exceeds 12.52 million, but no archive supports a precise Atlantic-wide addition. Claims of a confidently quantified total such as 20 million or 30 million usually combine demographic loss, unrecorded deaths and descendants who might otherwise have been born; those are different measures and should be labelled as such.

Denialists exploit uncertainty to dismiss the crime or shift responsibility exclusively onto African intermediaries. African rulers, merchants and military brokers did capture and sell people, but European and American states, chartered companies, financiers, shipowners and plantation buyers created, armed, insured and expanded the transatlantic market. Portugal and Brazil carried approximately 5.85 million embarked captives in the 1501–1866 SlaveVoyages estimates, more than any other national carrier grouping.

The 12.52 million embarked were not distributed mainly to the future United States. SlaveVoyages estimates indicate that fewer than 400,000 people—about 3.6% of Atlantic disembarkations during 1501–1866—landed in mainland North America. The largest flows went to Brazil and the Caribbean, where plantation economies consumed lives at extraordinary rates.

Nor does the shipping total measure slavery’s duration after arrival. Survivors and their descendants endured hereditary chattel slavery, forced reproduction, family separation, sale, punishment and uncompensated labor. Britain abolished slavery in most colonies through the Slavery Abolition Act 1833, effective 1 August 1834, while compensating slaveholders with £20 million authorized in 1833. The United States abolished slavery through the Thirteenth Amendment, ratified 6 December 1865. Brazil, the last state in the Americas to abolish it, enacted the Lei Áurea on 13 May 1888.

The number should therefore be used as a minimum frame for forced Atlantic embarkation, not as a complete casualty figure. It establishes the documented scale of organized deportation while leaving separate questions about African population loss, deaths outside ships, plantation mortality, accumulated wealth and present-day inequality. Those consequences belong within the archive’s records of atrocity, its chronological history, and its transparent treatment of quantitative evidence.

• SlaveVoyages: Trans-Atlantic Slave Trade Database — voyage records, estimates and methodology, continuously updated through 2026.
• David Eltis and David Richardson, Atlas of the Transatlantic Slave Trade — Yale University Press atlas, first published in 2010.
• Philip D. Curtin, The Atlantic Slave Trade: A Census — the 1969 quantitative reassessment that established modern census-based debate.
• Paul E. Lovejoy, “The Volume of the Atlantic Slave Trade: A Synthesis” — Journal of African History, 1982, revising export estimates.
• UNESCO, The Routes of Enslaved Peoples — international research and education program established in 1994.