The generally accepted figure today is approximately 100,000. The United States Holocaust Memorial Museum gives a range between 77,000 and 99,000, based on ranges of victims from each victim group (Serbs, Jews, Roma, and political prisoners). The Jasenovac Memorial itself lists more than 83,000 victims who are known by name, while acknowledging that this list is incomplete due to the destruction of records, so this should probably be viewed as the lower-bound figure. About half of the known victims are ethnic Serbs, with the majority of the others being Roma and Jews.

In the immediate postwar period, the Yugoslav government produced figures that we now know are greatly inflated, estimating 500,000 to 700,000 deaths. These figures were based on either witness testimonies or extrapolated based on lists of victim names or exhumed mass graves, which were obviously flawed ways of collecting this data (comparable to how the casualty figures produced by the Soviet investigatory commissions were greatly inflated, including the early estimate of 4,000,000 victims at Auschwitz). By the 1980s, research using more reliable methodologies (e.g. lists of documented victims) produced more realistic figures that were within the currently accepted range (83,000 to 85,000). After Croatia became independent, however, there was an opposite tendency by Croatian nationalists who wished to whitewash the legacy of the NDH to argue for much lower figures, in the range of 30,000, which we know are far too low based on documented deaths in the camp. During the last two decades, however, higher-quality research has produced the figures I cited above.

Beyond the sources I already cited, the best recent source in English is Ivo and Slavko Goldstein's The Holocaust in Croatia (U of Pittsburgh Press, 2016). Ivo Goldstein published a book on Jasenovac in 2018 (creatively titled Jasenovac, which is the kind of title I come up with when I write a book), which I'm told by my Serbo-Croatian-speaking colleagues is very good, but it hasn't been translated into English yet unfortunately. Hopefully it will be in the near future because there haven't been a lot of monograph-length publications on the Holocaust in the NDH since the early 2000s, which I why I recommended Goldstein and Goldstein (2016) as the most recent quality work on the subject.