The Stockholm International Peace Research Institute (SIPRI) reports in the 2013 edition of its annual global security review that Israel possesses some 80 nuclear warheads.
According to SIPRI, 50 of Israel's warheads are built for use atop medium-range ballistic missiles, while the other 30 are designed to be attached to bombs carried by aircraft. The Jewish state is also believed to have developed smaller, tactical nuclear munitions, such as artillery shells.
Israel is not a signatory to the Nuclear Non-Proliferation Treaty (NPT). While it is widely accepted that Israel possesses nuclear arms, Jerusalem maintains an official policy of ambiguity on the topic.
The report went on to note that both India and Pakistan, the world's newest nuclear powers, are in possession of 90-120 warheads each, while France, the UK and China have nuclear arsenals numbering in the hundreds. Russia and the US both possess many thousands of nuclear warheads.
France, the UK, China, Russia and the US are all signatories to the NPT. Nevertheless, SIPRI notes that all five nations have demonstrated that not only do they have no intention of relinquishing their nuclear stockpiles, they are actually further developing their nuclear weapons capabilities.
All told, there are believed to be 17,265 nuclear weapons in the world today, with approximately 4,400 of them classified as "operational."