There are about 12,700 nuclear weapons in the world that are located in the nuclear states of France, India, Israel, China, North Korea, Pakistan, Russia, the United Kingdom and the United States. In addition, there are around 100 nuclear weapons deployed through US/NATO in Belgium, Germany, Italy, the Netherlands and Turkey.
When the Nuclear Non-Proliferation Treaty (NPT) came into force in 1970, there were five states in the world that had nuclear weapons, these states were allowed to keep their nuclear weapons while they pursued effective measures towards disarmament. The five nuclear weapon states are France, China, Russia, United Kingdom and the United States.
States that acquired nuclear weapons after the NPT entered into force are called de facto nuclear weapon states. This includes countries such as India, Israel, North Korea and Pakistan. North Korea is the latest country to acquire nuclear weapons in 2006.
In addition to the nine nuclear weapon states, there are currently about 100 US nuclear weapons deployed through the United Stated and NATO in Belgium, Italy, the Netherlands, Turkey and Germany. There are also nuclear weapons on board ships and submarines in international waters.
Another category that is usually mentioned is threshold states. This is usually the name given to countries that have the technical ability to produce nuclear weapons, or that are suspected of having made preparations to produce their own nuclear weapons. The most talked about case in recent years has been Iran. In 2015, Iran, the US, Russia, China, the UK, France, Germany and the EU managed to negotiate an agreement on Iran’s nuclear energy program and a guarantee that Iran will not acquire nuclear weapons. The US left the agreement in 2018 and the future of the agreement is uncertain.
South Africa previously had nuclear weapons but dismantled its nuclear weapons program in 1990. There were also nuclear weapons deployed in the former Soviet states of Belarus, Kazakhstan and Ukraine, they were later returned to Russia or dismantled after the collapse of the Soviet Union.