Around two dozen countries have nuclear power, but only a few have nuclear weapons or are suspected of pursuing nuclear weapons. Check below to learn more about their nuclear programs.
Nuclear Weapons: United States
The United States has conducted more nuclear tests than the rest of the world combined and is the only country to have used a nuclear weapon in combat. The United States is also the only nuclear power with weapons deployed in other countries: Through NATO’s nuclear sharing program, there are U.S. bombs in Belgium, Germany, Italy, the Netherlands and Turkey.
Through various treaties, the United States and its former Cold War adversary, Russia, have been working together to reduce their vast nuclear arsenals, which are easily the two largest in the world. Both countries have the capability to launch nuclear weapons via land, air and sea.
As of December 2012, the United States was estimated to have about 2,150 operational warheads — weapons that are deployed or could be deployed at short notice. An additional 2,500 warheads are believed to be in reserve, and 3,000 more are retired and awaiting dismantlement, according to the Federation of American Scientists.
First test: 1945
Most recent test: 1992
Total tests: 1,054
Estimated warheads: 7,650 total – 2,150 operational
Of those, it is estimated that about 500 warheads are assigned to land-based missiles, 1,150 are assigned to nuclear submarines and 300 are ready to be deployed on aircraft. Also, as part of NATO’s nuclear sharing program, an additional 200 B61 gravity bombs are deployed in five NATO countries: Belgium, Germany, Italy, the Netherlands and Turkey. 2,500 in storage (reserve). 3,000 retired, awaiting dismantlement.
Nuclear weapons: Russia
Spies likely provided information to scientists in the former Soviet Union, cutting months and possibly years from the Soviets’ development of nuclear weapons. When the Soviets tested their first atomic device in 1949, they used almost the same design the United States had tested four years earlier and detonated over Nagasaki, Japan.
In recent years, Russia and the United States have been working together to reduce their vast arsenals, which are easily the two largest in the world. Both countries have the capability to launch nuclear weapons via land, air and sea.
As of December 2012, Russia was estimated to have about 1,720 operational warheads — weapons that are deployed or could be deployed at short notice. An additional 2,700 warheads are believed to be in reserve, and 4,000 more are retired and awaiting dismantlement, according to the Federation of American Scientists.
First test: 1949
Most recent test: 1990
Total tests: 715
Estimated warheads: 8,420 total – 1,720 operational
Of those, it is estimated that about 1,070 warheads are assigned to land-based missiles, 350 are assigned to nuclear submarines and 300 are ready to be deployed on aircraft. 2,700 in storage (reserve). 4,000 retired, awaiting dismantlement.
Nuclear weapons: United Kingdom
When the United States started the Manhattan Project, a group of scientists known as the “British mission” arrived to help. But when the United States passed a law in 1946 making it illegal to share information with other nations, the United Kingdom began its own nuclear program.
The U.S. legislation was amended in 1954, opening the door for renewed collaboration. More than half of the United Kingdom’s nuclear tests have been joint operations with the United States.
The United Kingdom has four submarines that carry nuclear missiles. Those four subs are the only way the country can launch a nuclear weapon. In 1998, it retired all air-delivered nuclear weapons.
First test: 1952
Most recent test: 1991
Total tests: 45
Estimated warheads: 225 total – Fewer than 160 operational
All are assigned to nuclear submarines, the country’s only launch mechanism. In 1998, it retired all air-delivered nuclear weapons. 65 in storage (reserve).
Nuclear weapons: France
France possesses the world’s third-largest nuclear arsenal, although it is a distant third to the United States and Russia.
After a defense review ordered by former President Jacques Chirac, France dismantled its land-based nuclear weapons in 1996 and reduced its total number of launch mechanisms by 50%.
Today, most of France’s estimated 300 warheads are deployed on its four nuclear submarines. The rest are either meant for aircraft, in maintenance or awaiting dismantlement, according to the Federation of American Scientists.
First test: 1960
Most recent test: 1996
Total tests: 210
Estimated warheads: 300 total – 290 operational
Of those, about 240 are thought to be assigned to nuclear submarines, while the other 50 are ready to be deployed on aircraft. France dismantled its land-based nuclear weapons in 1996. 10 in maintenance or awaiting dismantlement.
Nuclear weapons: China
China’s pursuit of nuclear weapons began in the 1950s after the U.S. moved nuclear assets into the Pacific during the Korean War. After successfully testing its first nuclear device in 1964, China conducted its first thermonuclear test just 32 months later — the shortest time between fission and fusion tests of all nuclear powers.
China is continuing to add to its arsenal, according to the Federation of American Scientists. As of December 2012, it was estimated to have about 140 warheads assigned to land-based missiles and 40 warheads assigned for aircraft. The rest are thought to be either awaiting dismantlement or being held for a future nuclear submarine. China is within two years of a nuclear sub, according to a recent report from the U.S.-China Economic and Security Review Commission.
First test: 1964
Most recent test: 1996
Total tests: 45
Estimated warheads: 240 total
Of China’s 240 estimated warheads, about 180 can be carried via aircraft or land-based missiles. The rest are either awaiting dismantlement or meant for nuclear submarines that are not yet available.
Nuclear weapons: India
India decided to build its own nuclear weapons after China began nuclear tests in the mid-1960s. India tested its first nuclear device in 1974. Three tests were conducted in May 1998, followed two days later by two more tests.
India has aircraft and land-based missiles capable of delivering nuclear payloads, and it is looking to add naval assets to its nuclear program. Like its rival, Pakistan, India is actively working to produce more warheads, according to the Federation of American Scientists.
First test: 1974
Most recent test: 1998
Total tests: 6
Estimated warheads: 80-100 total, 0 operational, 80-100 in storage
The warheads in storage can be carried via aircraft or land-based missiles. India is looking to add a sea-based launch mechanism.
Nuclear weapons: Pakistan
In 1972, following its third war with India, Pakistan secretly decided to start a nuclear program to match India’s developing capability. Pakistan responded to India’s nuclear tests in 1998 by announcing that it exploded six underground devices in the Chagai region near the Iranian border.
Like India, Pakistan is actively working to produce more warheads, according to the Federation of American Scientists. It has the ability to deliver nuclear payloads via aircraft and land-based missiles. It does not have a sea-based launch mechanism.
First test: 1998
Most recent test: 1998
Total tests: 6
Estimated warheads: 90-110 total, 0 operational, 90-110 in storage
The warheads in storage can be carried via aircraft or land-based missiles.
Nuclear weapons: North Korea
North Korea has conducted three underground nuclear tests, with the most recent coming in February. It has also carried out ballistic missile tests. But it is not thought to have brought the two technologies together yet.
In all, experts say the country has already separated enough plutonium for about 10 warheads. It has not, however, developed a way to weaponize them.
North Korea’s nuclear program began with the installation of a Soviet reactor in Yongbyon. In a 1994 agreement with the United States, North Korea pledged to suspend its weapons program in exchange for assistance building reactors to generate power. Eight years later, Pyongyang admitted to a secret nuclear weapons program and expelled inspectors from the International Atomic Energy Agency, the U.N.’s nuclear watchdog agency.
The U.N. Security Council has approved new sanctions against North Korea after each of its nuclear tests.
First test: 2006
Most recent test: 2013
Total tests: 3
Estimated warheads: Fewer than 10 total
Experts say the country has plutonium for about 10 warheads, but it is not thought to have the technology to deliver the weapons.
Nuclear weapons: Israel
Israel refuses to confirm or deny the widespread belief that it has the bomb, but it is thought to have about 80 atomic weapons and enough plutonium for as many as 200, according to the Federation of American Scientists.
Former Prime Minister Shimon Peres, in a 1998 television interview, said Israel began developing a “nuclear option” in the 1950s to prevent war. The center of Israel’s weapons program is reported to be the Negev Nuclear Research Center near the desert town of Dimona.
Over the years, Israel has acquired submarines and aircraft capable of carrying nuclear warheads, but it isn’t confirmed whether they’ve been modified to do so. Many estimate that Israel’s land-based Jericho missiles are also nuclear-capable.
No confirmed test yet.
Estimated warheads: 80 total
Israel’s nuclear capabilities have not been confirmed, but the Federation of American Scientists estimates that Israel has about 80 warheads in its arsenal.
Nuclear weapons: Iran
For the past decade there has been worldwide concern over Iran’s nuclear program. In November 2011, the International Atomic Energy Agency released a report saying it has “serious concerns” and “credible” information that Iran may be developing nuclear weapons.
Iran maintains that it is enriching uranium for civilian energy purposes only, but the IAEA says Iran has not been cooperating enough for the agency to verify whether the intent is solely for peaceful means. As a result, the U.N. Security Council and a number of Western nations have placed economic and arms-related sanctions on Iran.
There have been several meetings in the past year between Iran and the “P5+1” group, which consists of representatives from Germany and the five permanent members of the U.N. Security Council: China, France, Russia, the United Kingdom and the United States. But there is yet to be a diplomatic breakthrough.
Iran has been developing ballistic missiles since the 1980s, and it has the largest number of deployed missiles in the Middle East, according to a December 2012 report by the U.S. Congressional Research Service. But experts say these missiles aren’t nuclear-ready; even if Iran acquires a nuclear warhead, it would have to spend significant time and research on making it a deliverable weapon.
No confirmed test yet.
Estimated warheads: 0 total
Sources: Federation of American Scientists, CIA World Factbook, Nuclear Threat Initiative, U.S. Census Bureau