Where these data are not available , as in a number of cases , precise yields have been in dispute , especially when they are tied to questions of politics . The weapons used in the atomic bombings of Hiroshima and Nagasaki , for example , were highly individual and very idiosyncratic designs , and gauging their yield retrospectively has been quite difficult . The Hiroshima bomb , " Little Boy " , is estimated to have been between ( a 20 % margin of error ) , while the Nagasaki bomb , " Fat Man " , is estimated to be between ( a 10 % margin of error ) . Such apparently small changes in values can be important when trying to use the data from these bombings as reflective of how other bombs would behave in combat , and also result in differing assessments of how many " Hiroshima bombs " other weapons are equivalent to ( for example , the Ivy Mike hydrogen bomb was equivalent to either 867 or 578 Hiroshima weapons — a rhetorically quite substantial difference — depending on whether one uses the high or low figure for the calculation ) . Other disputed yields have included the massive Tsar Bomba , whose yield was claimed between being " only " or at a maximum of by differing political figures , either as a way for hyping the power of the bomb or as an attempt to undercut it
Ivy Mike
Ivy Mike
Nuclear weapon yield