Press Contacts: Daryl Kimball, Executive Director, (202) 463-8270 x107; Kelsey Davenport, Director for Nonproliferation Policy, (202) 463-8270 x102
Updated: August 2015
At the dawn of the nuclear age, the United States hoped to maintain a monopoly on its new weapon, but the secrets and the technology for making nuclear weapons soon spread. Four years after the United States conducted its first nuclear test explosion in July 1945 and dropped atomic bombs on the cities of Hiroshima and Nagasaki in August 1945, the Soviet Union conducted its first nuclear text explosion. The United Kingdom (1952), France (1960), and China (1964) followed. Seeking to prevent the nuclear weapon ranks from expanding further, the United States and other like-minded states negotiated the nuclear Nonproliferation Treaty (NPT) in 1968 and the Comprehensive Nuclear Test Ban Treaty (CTBT) in 1996.
Since the inception of the NPT, several states have abandoned nuclear weapons programs, but others have defied the NPT. India, Israel, and Pakistan have never signed the treaty and possess nuclear arsenals. Iraq initiated a secret nuclear program under Saddam Hussein before the 1991 Persian Gulf War. North Korea announced its withdrawal from the NPT in January 2003 and has tested nuclear devices since that time. Iran and Libya have pursued secret nuclear activities in violation of the treaty’s terms, and Syria is suspected of doing the same. Still, nuclear nonproliferation successes outnumber failures and dire forecasts decades ago that the world would be home to dozens of states armed with nuclear weapons have not come to pass.
At the time the the NPT was concluded, the nuclear stockpiles of the the United States and the Soviet Union/Russia numbered in the tens of thousands. Beginning in the 1970s, U.S. and Soviet/Russian leaders negotiated a series of bilateral arms control agreements and initiatives that limited, and later, reduced the size of their nuclear arsenals. Despite that progress, the United States and Russia still deploy more than 1,500 strategic warheads on several hundred bombers and missiles—far more than necessary to deter nuclear attack—and they are modernizing their nuclear delivery systems. If these weapons were used even in a “limited” way, the result would be catastrophic nuclear devastation.
Today, other nuclear arms states, China, India, and Pakistan, in particular, are all pursuing new ballistic missile, cruise missile, and sea-based nuclear delivery systems. In addition, Pakistan has dangerously lowered the threshold for nuclear weapons use by developing tactical nuclear weapons capabilities to counter perceived Indian conventional military threats. North Korea continues its nuclear pursuits in violation of its earlier denuclearization pledges. These arsenals, although smaller in number, are dangerous and destabilizing.
The nuclear-weapon states (NWS) are the five states—China, France, Russia, United Kingdom, and the United States—officially recognized as possessing nuclear weapons by the NPT. Although the treaty legitimizes these states’ nuclear arsenals, it also establishes that they are not supposed to build and maintain such weapons in perpetuity. Article VI of the treaty holds that each state-party is to “pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament.” In 2000, the five NWS committed themselves to an “unequivocal undertaking…to accomplish the total elimination of their nuclear arsenals.” But for now, the five continue to retain the bulk of their nuclear forces. Because of the secretive nature with which most governments treat information about their nuclear arsenals, most of the figures below are best estimates of each nuclear-weapon state’s nuclear holdings, including both strategic warheads and lower-yield devices referred to as tactical weapons. Russia and the United States also retain thousands of retired warheads planned for dismantlement, not included here.
China: About 250 total warheads.
France: 300 total warheads.
Russia: According to the March 2015 New START numbers, Russia has 1,582 strategic warheads deployed on 515 ICBMs, SLBMs, and strategic bombers . The Federation of American Scientists estimates Russia has several thousand nondeployed strategic warheads and approximately 2,000 tactical nuclear warheads. An additional 3,200 are awaiting dismantlement.
United Kingdom: About 120 strategic warheads, of which no more than 40 are deployed at sea at any given time. The total stockpile is up to 225 weapons.
United States: According to the March 2015 New START declaration, the United States has 1,597 strategic nuclear warheads deployed on 785 ICBMs, SLBMs, and strategic bombers . The Federation of American Scientists estimates that the United States' nondeployed strategic arsenal is approximately 2,800 warheads and the U.S. tactical nuclear arsenal numbers 500 warheads. According to the U.S. State Department, the United States possessed 4,717 active nuclear warheads as of September 30, 2014 , including tactical, strategic, and nondeployed weapons. Additional warheads are retired and await dismantlement.
Non-NPT Nuclear Weapons Possessors:
Three states—India, Israel, and Pakistan—never joined the NPT and are known to possess nuclear weapons. Claiming its nuclear program was for peaceful purposes, India first tested a nuclear explosive device in 1974. That test spurred Pakistan to ramp up work on its secret nuclear weapons program. India and Pakistan both publicly demonstrated their nuclear weapon capabilities with a round of tit-for-tat nuclear tests in May 1998. Israel has not publicly conducted a nuclear test, does not admit to or deny having nuclear weapons, and states that it will not be the first to introduce nuclear weapons in the Middle East. Nevertheless, Israel is universally believed to possess nuclear arms, although it is unclear how many weapons Israel possesses. The following arsenal estimates are based on the amount of fissile material—highly enriched uranium and plutonium—that each of the states is estimated to have produced. Fissile material is the key element for making nuclear weapons. India and Israel are believed to use plutonium in their weapons, while Pakistan is thought to use highly enriched uranium.
India: Between 90-110 nuclear warheads.
Israel: Between 80-100 nuclear warheads, with fissile material for up to 200.
Pakistan: Between 100 to 120 nuclear warheads.
States of Immediate Proliferation Concern:
Iran is pursuing a uranium-enrichment program and other projects that could provide it with the capability to produce bomb-grade fissile material and develop nuclear weapons within the next several years. In contrast, North Korea has the material to produce a small number of nuclear weapons, announced its withdrawal from the NPT, and tested nuclear devices. Uncertainty persists about how many additional nuclear devices North Korea has assembled beyond those it has tested. In September 2005, Pyongyang “committed to abandoning all nuclear weapons and existing nuclear programs.”
Iran: No known weapons or sufficient fissile material stockpiles to build weapons. However, the International Atomic Energy Agency (IAEA), the institution charged with verifying that states are not illicitly building nuclear weapons, concluded in 2003 that Iran had undertaken covert nuclear activities to establish the capacity to indigenously produce fissile material. In July 2015, Iran and six world powers negotiated a long-term agreement to verifiably and significantly Iran's capacity to produce material for nuclear weapons, and the IAEA is continuing its investigation and monitoring of Tehran’s nuclear program.
North Korea: Is estimated to have 6-8 plutonium based warheads as of 2014. North Korea unveiled a centrifuge facility in 2010, buts ability to produce highly-enriched uranium for weapons remains unclear. In August 2013, North Korea restarted the heavy-water reactor it used to extract plutonium in the past for its nuclear warheads, although operation of the reactor since August has not been constant. Experts estimate it will be about 18 months before the first new bomb-ready plutonium will be separated from the spent fuel.
Syria: In September 2007, Israel conducted an airstrike on what U.S. officials have alleged was the construction site of a nuclear research reactor similar to North Korea’s Yongbyon reactor. Intelligence officials briefed members of congress on the airstrike eight months later in April 2008, discussing the evidence leading to their judgment that the site was an undeclared nuclear reactor. While the extent of Syrian-North Korean nuclear cooperation is unclear, it is believed to have begun in 1997. Subsequent IAEA investigations into the U.S. claims uncovered traces of undeclared man-made uranium particles at both the site of the destroyed facility and Syria’s declared research reactor. Syria has failed to provide adequate cooperation to the IAEA in order to clarify the nature of the destroyed facility and procurement efforts that could be related to a nuclear program.
States That Had Nuclear Weapons or Nuclear Weapons Programs at One Time:
Belarus, Kazakhstan, and Ukraine inherited nuclear weapons following the Soviet Union’s 1991 collapse, but returned them to Russia and joined the NPT as non-nuclear-weapon states. South Africa secretly developed and dismantled a small number of nuclear warheads and also joined the NPT in 1991. Iraq had an active nuclear weapons program prior to the 1991 Persian Gulf War, but was forced to verifiably dismantle it under the supervision of UN inspectors. The U.S.-led March 2003 invasion of Iraq and subsequent capture of Iraqi leader Saddam Hussein definitively ended his regime’s pursuit of nuclear weapons. Libya voluntarily renounced its secret nuclear weapons efforts in December 2003. Argentina, Brazil, South Korea, and Taiwan also shelved nuclear weapons programs.
1. In April 2015, the U.S. State Department issued the latest fact sheet on its data exchange with Russia under New START, sharing the numbers of deployed nuclear warheads and New START-accountable delivery systems held by each country.
2. Revised numbers released on April 27, 2015, by the U.S. State Department. Included in this stockpile active warheads which are operational and deployed or ready to be deployed, and inactive warheads which are maintained "in a non-operational status, and have their tritium bottle removed." It does not include warheads that have been retired and are awaiting dismantlement.
Sources: Arms Control Association, Federation of American Scientists, International Panel on Fissile Materials, U.S. Department of Defense, and U.S. Department of State.