More than two decades after the Cold War ended, the world’s combined inventory of nuclear warheads remains at a very high level: approximately 15,700. Of these, around 4,100 warheads are considered operational, of which about 1,800 US and Russian warheads are on high alert, ready for use on short notice.
Despite significant reductions in US, Russian, French and British nuclear forces compared with Cold War levels, all the nuclear weapon states continue to modernize their remaining nuclear forces and appear committed to retaining nuclear weapons for the indefinite future. For an overview of global modernization programs, see this 2014 article.
The exact number of nuclear weapons in each country’s possession is a closely held national secret. Despite this limitation, however, publicly available information, careful analysis of historical records, and occasional leaks make it possible to make best estimates about the size and composition of the national nuclear weapon stockpiles:
Status of World Nuclear Forces 2015*
| United States
| United Kingdom
| North Korea
|* All numbers are approximate estimates and further described in the Nuclear Notebook in the Bulletin of the Atomic Scientists, and the nuclear appendix in the SIPRI Yearbook. See also status and 10-year projection of U.S. and Russian forces. Additional reports are published on the FAS Strategic Security Blog. Unlike those publications, this table is updated continuously as new information becomes available. Current update: April 28, 2015.
a This number is higher than the aggregate data under the New START treaty because this table also counts bomber weapons at bomber bases as deployed. Detailed overview of Russian forces as of 2014 is here (2015 update in May).
b All are declared to be in central storage. Several thousand retired non-strategic warheads are awaiting dismantlement.
c Includes all non-strategic warheads, strategic warheads assigned to delivery systems in overhaul, and most bomber weapons.
d In addition to the 4,500 in the military stockpile, an estimated 3,000 retired warheads are estimated to be awaiting dismantlement. Details are scarce, but we estimate that Russia is dismantling 500-1,000 retired warheads per year. See 2015 overview of Russian forces here. See also this blog.
e This number is higher than the aggregate data released under the New START data because this table also counts bomber weapons on bomber bases as deployed. See 2015 overview of U.S. forces here.
f Approximately 180 B61 bombs are deployed in Europe at six bases in five countries (Belgium, Germany, Italy, Netherlands and Turkey). For details, see here and here.
g Non-deployed reserve includes an estimated 2,320 strategic and 300 non-strategic warheads in central storage.
h The U.S. government declared in April 2015 that its stockpile included 4,717 warheads as of September 2014. Since then, a small number of warheads are thought to have been retired.
i In addition to the roughly 4,700 warheads in the military stockpile, the U.S. government in April 2015 announced that approximately 2,500 retired warheads are awaiting dismantlement. In addition, close to 20,000 plutonium cores (pits) and some 5,000 Canned Assemblies (secondaries) from dismantled warheads are in storage at the Pantex Plant in Texas and Y-12 plant in Tennessee. For detailed overview of U.S. forces as of 2015, see here.
j Only weapons for France’s single aircraft carrier are not considered deployed, although it is possible that warhead loadings on some submarines missiles have been reduced. For a review of the French arsenal, see this article.
k China is thought to have “several hundred warheads,” far less than the 1,600-3,000 that have been suggested by some. None of the warheads are thought to be fully deployed but kept in storage under central control. The exstence of a Chinese non-strategic nuclear arsenal is uncertain. The Chinese arsenal is increasing with production of new warheads for DF-31/31A and JL-2 missiles. Detailed overview of Chinese forces as of 2013 is here.
l The number of warheads on each submarine is being lowered from 48 to 40, and may already have been completed. This will lower the number of “operationally available” warheads from 160 to 120. By the mid-2020s, the stockpile will be reduced to “not more than 180.” Detailed overview of British forces is here.
m Although Israel has produced enough plutonium for 100-200 warheads, the number of delivery platforms and estimates made by the U.S. intelligence community suggest that the stockpile might include approximately 80 warheads. Detailed 2014 overview of Israeli forces is here.
n None of Pakistan’s warheads are thought to be deployed but kept in central storage, most in the southern parts of the country. More warheads are in production. Detailed overview here.
o Indian nuclear warheads are not deployed but in central storage. More warheads are in production. Detailed overview of Indian forces is here.
p Despite three North Korean nuclear tests, there is no publicly available evidence that North Korea has miniaturized and operationalized its nuclear weapons capability. A 2013 world survey by the U.S. Air Force National Air and Space Intelligence Center (NASIC) does not credit any of North Korea’s ballistic missiles with any nuclear capability.
q Numbers may not add up due to rounding and uncertainty about the operational status of the four lesser nuclear weapons states and the uncertainty about the size of the total inventories of three of the five initial nuclear powers.
The information available for each country varies greatly, ranging from the most transparent nuclear weapons state (United States) to the most opaque (North Korea). Accordingly, while the estimate for the United States is based on “real” numbers, the estimates for several of the other nuclear weapon states are highly uncertain.