Contact: Kelsey Davenport, Director for Nonproliferation Policy, (202) 463-8270 x102; Daryl G. Kimball, Executive Director, (202) 463-8270 x107.
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 building the atomic bomb soon spread. The United States conducted its first nuclear test explosion in July 1945 and dropped two atomic bombs on the cities of Hiroshima and Nagasaki, Japan, in August 1945. Just four years later, the Soviet Union conducted its first nuclear test 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 countries negotiated the nuclear Nonproliferation Treaty (NPT) in 1968 and the Comprehensive Nuclear Test Ban Treaty (CTBT) in 1996.
India, Israel, and Pakistan never signed the NPT 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 successfully tested advanced 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 having done the same. Still, nuclear nonproliferation successes outnumber failures, and dire decades-old forecasts that the world would soon be home to dozens of nuclear-armed states have not come to pass.
At the time the NPT was concluded, the nuclear stockpiles of both 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 helped to reduce, the size of their nuclear arsenals.
Today, the United States deploys 1,419 and Russia deploys 1,549 strategic warheads on several hundred bombers and missiles, and are modernizing their nuclear delivery systems. Warheads are counted using the provisions of the New START agreement, which was extended for 5 years in January 2021. Russia suspended its participation in the treaty on Feb. 21, 2023; in response, the United States instituted countermeasures limiting information sharing and inspections. However, both the U.S. and Russia have committed to the treaty’s central limits on strategic force deployments until 2026.
New START caps each country at 1,550 strategic deployed warheads and attributes one deployed warhead per deployed heavy bomber, no matter how many warheads each bomber carries. Warheads on deployed ICBMs and SLBMs are counted by the number of re-entry vehicles on the missile. Each re-entry vehicle can carry one warhead.
The United States, Russia, and China also possess smaller numbers of non-strategic (or tactical) nuclear warheads, which are shorter-range, lower-yield weapons that are not subject to any treaty limits.
China, India, and Pakistan are all pursuing new ballistic missiles, cruise missiles, and sea-based nuclear delivery systems. North Korea continues its nuclear pursuits in violation of its earlier denuclearization pledges.
The world's nuclear-armed states possess a combined total of about 12,100 nuclear warheads as of March 2024.
Nuclear-Weapon States:
The nuclear-weapon states (NWS) are the five states—China, France, Russia, the United Kingdom, and the United States—officially recognized as possessing nuclear weapons by the NPT. The treaty recognizes these states’ nuclear arsenals, but under Article VI of the NPT, they are not supposed to build and maintain such weapons in perpetuity. In 2000, the NWS committed themselves to an “unequivocal undertaking…to accomplish the total elimination of their nuclear arsenals.” 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 shorter-range and lower-yield nuclear bombs, generally referred to as tactical nuclear weapons.
- According to the September 2022 New START declaration, Russia deploys 1,549 strategic warheads on 540 strategic delivery systems (intercontinental ballistic missiles, submarine-launched ballistic missiles, and heavy bombers). Due to Russia’s suspension of the New START Treaty in February 2022, it did not fulfill its treaty obligations to provide updated data. However, both Russia and the United States have committed to adhering by treaty limits until 2026.
- The U.S. intelligence community assesses that, as of December 2022, Russia also maintains an arsenal of 1000-2000 non-strategic nuclear warheads not limited by the New START Treaty.
- The Federation of American Scientists (FAS) estimates that Russia's military stockpile consists of approximately 4,380 nuclear warheads, with 1,200 additional retired warheads awaiting dismantlement, as of March 2024.
- According to the March 2023 New START declaration, the United States deploys 1,419 strategic nuclear warheads on 662 strategic delivery systems (intercontinental ballistic missiles, submarine-launched ballistic missiles, and heavy bombers).
- The United States also has an estimated 100 B-61 nuclear gravity bombs that are forward-deployed at six NATO bases in five European countries: Aviano and Ghedi in Italy; Büchel in Germany; Incirlik in Turkey; Kleine Brogel in Belgium; and Volkel in the Netherlands.
- On July 19, 2024, the U.S. Energy Department issued a declassification announcement indicating that the total number of U.S. “active” and “inactive” warheads is 3,748 as of September 2023. The stockpile figures do not include retired warheads and those awaiting dismantlement, which the department says number around 2,000 warheads. FAS independently estimates the current military stockpile stands at 3,708 warheads, with 1,336 retired warheads awaiting dismantlement, for a total of 5,044 warheads as of May 2024. The discrepancy in the number of retired warheads is attributable to a slower than anticipated rate of dismantlements of retired warheads.
- Independent researchers estimate that China has approximately 440 nuclear warheads for delivery by land-based ballistic missiles, sea-based ballistic missiles, and bombers. Of that total, they estimate China has assigned approximately 310 warheads to 206 strategic launchers (intercontinental ballistic missiles and submarine-launched ballistic missiles.) Additionally, around 60 warheads are thought to have been produced for eventually arming additional road-mobile and silo-based missiles and bombers.
- Since the 1990s, China has continually modernized its nuclear forces, though the number and types of weapons fielded have expanded significantly in recent years. As of October 2023, the Defense Department assessed that China has a total of 500 nuclear weapons and, if it remains on its current trajectory, may have up to 1000 deliverable nuclear warheads by 2030.
- France has a military stockpile of 290 operational warheads available for deployment on 98 strategic delivery systems, as of January 2022. This consists of 48 submarine-launched ballistic missiles, and 50 air-launched cruise missiles allocated for dual-capable land and carrier-based fighter aircraft.
- The French government has committed to a long-term modernization program for its nuclear forces but does not plan to increase the size of its nuclear stockpile.
- As of January 2022, the United Kingdom has a military stockpile of 225 warheads, of which an estimated 120 are operationally available for deployment on 48 submarine-launched ballistic missiles, and 105 are in storage.
- The United Kingdom possesses a total of four Vanguard-class Trident nuclear-powered ballistic missile submarines, which together form its exclusively sea-based nuclear deterrent.
Non-NPT Nuclear Weapons Possessors:
India, Pakistan, and Israel never joined the NPT and are known to possess nuclear weapons. 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 but is universally believed to possess nuclear arms.
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 is estimated to possess up to 172 nuclear warheads.
- Pakistan is estimated to possess approximately 170 nuclear warheads.
- Israel is estimated to have 90 nuclear warheads, with fissile material stockpiles for about 200 weapons.
- Israel does not admit nor 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 stored in a partially disassembled state, although it is unclear exactly how many.
States that Declared Their Withdrawal from the NPT:
North Korea joined the NPT as a non-nuclear weapon state but announced its withdrawal from the NPT in 2003 --a move that has not been legally recognized by the other NPT member states. North Korea has tested nuclear devices and nuclear-capable ballistic missiles. Uncertainty persists about how many nuclear devices North Korea has assembled.
- North Korea is estimated to have approximately 30 nuclear warheads and likely possesses additional fissile material that is not weaponized, but there is a high degree of uncertainty surrounding these estimates.
- North Korea currently operates its 5-megawatt heavy-water graphite-moderated reactor to extract plutonium for its nuclear warheads. North Korea has uranium enrichment technology and a known uranium enrichment facility at Yongbyon. It likely operates additional covert uranium enrichment facilities at other locations.
- North Korea has developed nuclear capable missiles of various ranges, including ICBMs, and claims to have developed tactical nuclear warheads.
States of Immediate Proliferation Concern:
Iran is a threshold state—it has developed the necessary capacities to build nuclear weapons. Tehran has threatened to withdraw from the NPT and to pursue a nuclear deterrent if its security considerations shift.
- Iran ratified the NPT in 1970 but pursued illicit nuclear activities, including an organized nuclear weapons program, through 2003, according to the International Atomic Energy Agency (IAEA) and the US intelligence community.
- The IAEA reported Iran to the Security Council in 2006 after Tehran failed to cooperate with the agency's investigation into discrepancies surrounding Iran's nuclear program. The Security Council passed six resolutions directed at Iran's nuclear program from 2006-2010.
- In 2007, the United States intelligence community concluded in an unclassified national intelligence estimate that "Iran has the scientific, technical and industrial capacity eventually to produce nuclear weapons if it decides to do so."
- In July 2015, Iran and six world powers negotiated an agreement to limit the country's nuclear program and enhance transparency in exchange for relief from sanctions directed at Iran for breaching its NPT commitments. In May 2018, the United States withdrew from the JCPOA and reimposed sanctions on Iran. The following year Iran began breaching the JCPOA's nuclear restrictions. Tehran maintains that it does not intend to pursue nuclear weapons and that its actions are a response to the U.S. withdrawal from the nuclear deal and reimposition of sanctions. (Continued coverage of the JCPOA can be found in Arms Control Today and the P4+1 and Iran Nuclear Deal Alert.)
- The US intelligence community assessed in the 2024 Worldwide Threat Assessment that Iran has not resumed key nuclear weapons-related activities but its nuclear advances better position it to develop nuclear weapons if the decision is made to do so.
- Iran has accumulated enough uranium enriched to 60 percent to build nuclear weapons, but the warhead would be large, unwieldy, and inconsistent with the weapons-related work Iran did prior to 2003.
- The IAEA is currently investigating evidence that Iran conducted activities involving uranium as part of the 2003 program that were not declared to the IAEA as required under the safeguards investigation.
- Iranian officials continue to deny that the country pursued nuclear weapons in the past but began suggesting after an April 2024 attack on Israel that the country will rethink its nuclear doctrine if security conditions change or its nuclear facilities are attacked.
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.
- The apartheid South African government secretly developed a small number of nuclear weapons. South Africa joined the NPT in 1991 and dismantled its entire nuclear weapons program prior to its transition to a multi-racial democracy in 1994.
- 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 United States invaded Iraq in 2003 under the Bush administration’s rationale of preventing Iraq from acquiring weapons of mass destruction. However, Iraq’s nuclear program had remained dormant since its dismantlement in the 1990s and the country did not have ready stockpiles of chemical or biological weapons.
- Libya voluntarily renounced its secret nuclear weapons efforts in December 2003.
- The IAEA is seeking clarification from Syria regarding its nuclear program. In 2007, Israel bombed a reactor under construction at Al Kibar. Evidence suggests Syria was constructing the reactor as part of an illicit nuclear weapons effort.
- Argentina, Brazil, South Korea, Sweden, Australia, and Taiwan also once pursued nuclear weapons programs.
Sources: Arms Control Association, Federation of American Scientists, International Panel on Fissile Materials, U.S. Department of Defense, U.S. Department of State, and Stockholm International Peace Research Institute.