As of early 2025, there are nine countries that own an estimated total of 12,241 nuclear warheads, with Russia and the US possessing the vast majority, according to Sipri and the Federation of American Scientists, a non-profit that focuses on promoting transparency about nuclear arsenals.
The United Kingdom, France, China, India, Pakistan, North Korea and Israel are believed to own the remaining 13% of nuclear weapons, according to the federation.
Some of those warheads have been retired but are still intact and have not yet been dismantled, according to FAS estimates.
With about 9614 in the military stockpiles for use by missiles, aircraft, ships and submarines, FAS researchers have classified 3912 of those warheads as “deployed strategic and nonstrategic warheads”, meaning that they are either on intercontinental missiles or heavy bomber bases, or are located on bases with operational short-range delivery systems.
Countries typically keep the exact sizes of their nuclear stockpiles secret, so nuclear weapons watchdogs and analysts can only provide estimates on each country’s numbers.
Only the US, Britain, and France have ever publicly disclosed information on the size of their nuclear arsenals, according to Sipri, and the FAS notes that nuclear transparency has decreased in recent years.
Israel, thought to be the only nuclear-armed power in the Middle East, has a policy of not confirming or denying that it possesses nuclear weapons – but is estimated to have around 90 nuclear weapons in its possession.
FAS researchers say they based their estimations on “publicly available information, careful analysis of historical records, and occasional leaks”, and they are in line with similar estimations made by other research institutes and watchdog organisations.
What countries host nuclear weapons?
While only nine countries own nuclear weapons, six countries are currently hosting nuclear weapons on their soil for other countries – five for the US, and one for Russia, according to experts.
Nato operates a nuclear sharing agreement where the US stores a number of nuclear weapons in certain locations in Europe.
Historically, the US and its European partners have been tight-lipped about where the weapons are – but it has widely been considered an open secret that they are stored on bases in Italy, the Netherlands, Germany, Turkey, and Belgium.
The countries are storing a combined total of about 100 nuclear weapons belonging to the US within their borders, according to the International Campaign to Abolish Nuclear Weapons (ICAN), a coalition of organisations seeking to eliminate and ban nuclear weapons.
Greece no longer hosts nuclear weapons for the US but has a reserve squadron for contingency missions, FAS researchers said.
These weapons are all under the control of the US, but housing these weapons within these allied states acts “as a way of assuring the engagement of the US in their defence”, said Lukasz Kulesa, the director of proliferation and nuclear policy at the Royal United Services Institute in Britain. “It’s confirming that the US has skin in the fight,” Kulesa said.
Storing the weapons with other countries also acts as a non-proliferation tool, Kulesa said. “If they have these weapons from the US on their soil, then these countries will not consider getting their own nuclear weapons,” he said.
In March 2023, Russian President Vladimir Putin announced plans to store tactical nuclear weapons in neighbouring Belarus.
Three months later, Belarusian President Alexander Lukashenko, a longtime Putin supporter, claimed that his country had begun taking delivery of Russian tactical nuclear weapons.
However, Sipri noted in its 2025 report that while both Russia and Belarus have continued to claim that nuclear weapons have been deployed to Belarus, “there was no conclusive evidence of this deployment”. ICAN also lists the quantity of warheads hosted in Belarus as “unknown”.
What is the future of the global nuclear weapon arsenal?
At the height of the Cold War, the total global inventory of nuclear warheads reached 70,000. The trend over the past few decades has been towards decreasing the number of stockpiles – but with conflicts threatening the national security of countries around the world, that time may be over, experts said.
“The signs are that a new qualitative nuclear arms race is gearing up and, compared with the last one, the risks are likely to be more diverse and more serious,” Sipri director Dan Smith wrote in the 2025 Sipri yearbook report on nuclear disarmament and international security.
Kulesa said he expected to see countries’ stockpiles stay steady or increase.
“Right now, we are in a situation where we have nine nuclear weapon possessors that in most cases see the value that nuclear weapons have for their security doctrines,” he said.
However, Kulesa added, common knowledge of Israel’s nuclear arsenal has not deterred other countries or armed groups from attacking it, and Western states have sent aid to Kyiv despite Russia’s nuclear threats – suggesting that “the traditional approach to nuclear deterrence”, or the belief that the fear of a nuclear attack brings “some degree of stability”, is flawed.
“The idea was that increasing your defensive potential will discourage the other side from attacking in the first place, but it is actually being seen by the other side as decreasing the deterrence value of their own forces,” Kulesa said.
“You have, in a sense, a circle in which any decision to boost defence will lead to an increase of nuclear forces.”
