The world's nuclear arsenal has shrunk from 70,300 active warheads to about 3,900
Nine countries are generally believed to hold nuclear weapons, though only eight admit it. At the Cold War peak in 1986 there were some 70,300 active warheads; by 2026 the Federation of American Scientists counts roughly 3,912 active among 12,187 in total. Many retired weapons were merely stored or partly dismantled, not destroyed.
The club grew in a clear sequence of first tests: the United States in 1945, the Soviet Union in 1949, Britain in 1952, France in 1960, China in 1964, India in 1974, Pakistan in 1998 and North Korea in 2006. Israel is thought to have acquired weapons around 1967 but has never tested openly or confirmed them. The first five, having exploded a device before 1967, are the recognised weapon states under the Non-Proliferation Treaty and also the Security Council's permanent members. India, Pakistan and Israel never signed; North Korea joined in 1985 and announced its withdrawal in 2003.
The US built the first bombs through the Manhattan Project with Britain and Canada, fearing Nazi Germany would get there first. The Trinity test came on 16 July 1945, and Hiroshima and Nagasaki are still the only cities ever struck by them in wartime, both by the US. Its stockpile peaked at 31,175 warheads in 1966. The Soviet programme, helped by atomic spies, peaked higher, at about 45,000 in 1986, and produced the most powerful explosion ever set off, the Tsar Bomba, designed for 100 megatons and detonated at 50.
Others chose different paths. China went from its first fission test to a hydrogen bomb in 32 months, the fastest such leap on record, and is the only treaty weapon state with an unconditional no-first-use pledge; estimates put its arsenal around 500 in 2024 and growing. France built its force largely on its own research after the Suez crisis. Britain relies on four Vanguard-class submarines carrying Trident missiles.
Some countries walked away. South Africa built weapons by 1982, dismantled them around 1989 and joined the treaty in 1991. After the Soviet collapse, Ukraine, Kazakhstan and Belarus sent the warheads on their soil to Russia and joined as non-weapon states. Meanwhile five NATO members, including Germany, Italy and Turkey, host American bombs on their soil, and at least 23 countries hosted foreign nuclear weapons during the Cold War.
Source: List of states with nuclear weapons
