Calculated from the atomic weight and the atomic volume. The unit cell, containing 16 atoms, has a volume of 319.96 cubic Å, according to Siegfried S. Hecker (2000). "Plutonium and its alloys: from atoms to microstructure"(PDF). Los Alamos Science. 26: 331.. This gives a density for 238Pu of (1.66053906660×10−24g/dalton×238.0495599 daltons/atom×16 atoms/unit cell)/(319.96 Å3/unit cell × 10−24cc/Å3) or 19.8 g/cc.
Moss, William; Eckhardt, Roger (1995). "The Human Plutonium Injection Experiments"(PDF). Los Alamos Science. Radiation Protection and the Human Radiation Experiments (23): 177–223. Retrieved 13 November 2012.
Glenn T. Seaborg (September 1981). Plutonium Story. Actinides-1981 conference, Pacific Grove, CA, USA, 10 Sep 1981. Lawrence Berkeley Laboratory, University of California. LBL-13492, DE82 004551.
Rowland, R.E., and Durbin, P.W. Survival, causes of death, and estimated tissue doses in a group of human beings injected with plutonium. United States: N. p., 1975. Web.