There are five nations which are officially recognized as "nuclear weapons states" which is a
status given by the Non-Proliferation Treaty. In the order when they acquired nuclear
weapons they are: America, the Soviet Union/Russia, United Kingdom, France, and China.
Since the nuclear tests by India and Pakistan in May 1998 these two nations have stated
publicly that they have a nuclear arsenal. However international organizations do not
formally recognize this status (previously India tested a "peaceful nuclear explosion" in
1974). In addition, Israel has a nuclear arsenal but has not admitted this. Three smaller
states of the former Soviet Union which inherited nuclear arsenals - Ukraine, Kazakhstan,
and Belarus -have handed over all nuclear warheads to Russia. The Democratic People’s
Republic of Korea (DPRK) has tested a nuclear device in 2006, 2009 and 2013. However there
are different opinions in the international community with regard to the DPRK’s ability to
weaponize a test device and put it on a ballistic missile.
South Africa is the only nation that has internally developed its own nuclear weapons
(researchers believe they had a gun design) and has then unilaterally disarmed as a result of
special political circumstances (when the system of Apartheid collapsed).
In the graph (above) it is clear that Russia and America are dominant with regard to total and
deployed nuclear warhead stockpiles. The next graph shows the total stockpile numbers
from 1945 through the present day: