Global nuclear warhead count rises for the first time in years

The world’s nine nuclear-armed states expanded their arsenals in 2025, according to a new assessment from the Stockholm International Peace Research Institute. Researchers Hans M. Kristensen and Matt Korda found that most countries deployed new nuclear-armed or nuclear-capable weapons during the year, even as the overall number of warheads in the world continued to decline.

SIPRI counted an estimated 12,187 nuclear warheads worldwide as of January 2026. About 9,745 of those sit in military stockpiles ready for potential use, roughly 130 more than a year earlier. An estimated 4,012 warheads were deployed on missiles and at bomber bases, an increase of about 100 from January 2025. SIPRI attributes much of that rise to a reassessment of Russian deployments and new estimates of Chinese and Indian warheads placed with operational forces.

The total figure keeps falling only because the United States and Russia are dismantling retired weapons faster than new ones are built elsewhere. Both countries still hold more than 1,000 retired warheads awaiting dismantlement. SIPRI’s researchers say the pace of dismantlement appears to be slowing, and it may soon fall behind the rate at which new warheads enter global stockpiles.

The United States and Russia together hold about 83 percent of the world’s deployable warheads and nearly 86 percent of the total inventory, though that share has been shrinking slightly each year as other arsenals grow. Both countries are running extensive modernization programs covering their delivery systems, warheads and production infrastructure, and both have been hit by delays and cost overruns. The U.S. Sentinel intercontinental ballistic missile program is running at least four years late and roughly 81 percent over its original cost estimate, according to the report. Russia’s Sarmat heavy ICBM is more than eight years behind schedule, and a 2025 test reportedly damaged its launch infrastructure.

China’s arsenal grew from about 600 warheads to roughly 620 over the year and is expected to keep expanding through the next decade. India’s stockpile rose slightly to about 190 warheads, while Pakistan held steady at around 170. North Korea is believed to have assembled about 60 warheads, though SIPRI says it may have enough fissile material for at least 90. Israel’s stockpile is estimated at 90 warheads, unchanged from the previous year. Britain’s declared warhead count held at 225, though the government has said it plans to raise that ceiling to 260 and has stopped publicly disclosing deployment details. France’s stockpile stayed near 290 warheads.

One factor complicating outside estimates: the 2010 New START treaty between the U.S. and Russia expired without replacement in February 2026, cutting off a longstanding source of official data on American and Russian strategic deployments. SIPRI says nuclear-armed states in general are becoming less transparent about their arsenals, making independent verification harder across the board.

The report also points to shifts in how countries plan to use these weapons. Russia’s 2024 doctrine update widened the circumstances under which Moscow says it could use nuclear weapons, a change SIPRI links to the war in Ukraine. Belarus has said Russian nuclear weapons are stationed on its territory, and Russia has shown video of its Oreshnik missile, which can carry conventional or nuclear warheads, operating inside the country.

In Europe, Britain and France signed the Northwood Declaration in July 2025, agreeing their nuclear forces could be coordinated in response to an extreme threat to Europe. Britain also announced plans to buy F-35A aircraft and rejoin NATO’s nuclear-sharing mission, which would make it the sixth NATO host nation for U.S. nuclear weapons. Poland, Finland and Sweden have all discussed hosting U.S. nuclear weapons in some capacity in recent years.

China’s expanding missile force, meanwhile, has drawn attention for a possible shift away from its historic practice of storing warheads separately from launchers. The Pentagon has assessed that China loaded more than 100 missiles into three new silo fields in 2025, though there’s no public evidence the missiles are armed. SIPRI estimates China may have deployed a small number of warheads, perhaps up to 34, with operational forces as of January 2026.

South Asia saw its own escalation risk in 2025. India and Pakistan fought their most serious armed conflict in decades in May, involving Indian strikes on Pakistani bases assessed to have nuclear missions. Both sides avoided crossing into nuclear territory, but SIPRI describes the clash as a shift in regional dynamics that leaves the risk of rapid escalation as an ongoing concern.