As the Israel–Iran war escalates and global security tensions mount, the spectre of nuclear conflict has once again moved to the forefront. But beyond the world’s largest stockpiles, it is regional rivalries that are drawing renewed scrutiny. According to the Stockholm International Peace Research Institute’s (SIPRI) Yearbook 2025, India has not only widened its nuclear lead over Pakistan in terms of warhead numbers, but is also making significant technological advances in missile systems and delivery capability.
SIPRI, an independent institute based in Sweden, has tracked global armaments, disarmament, and international security trends since 1966. Its annual yearbook is widely regarded as one of the most credible assessments of the world’s nuclear balance.
So, who’s leading the nuclear race in 2025 and who’s catching up fast? SIPRI’s new data shows how each country is rearming in a more dangerous world.
Russia
Russia remains the world’s leading nuclear power in terms of total warheads. SIPRI estimates it holds roughly 5,880 nuclear weapons, with many deployed on missiles and submarines, and around 2,100 kept on high operational alert, ready to launch at short notice.
United States
Closely behind, the United States possesses an estimated 5,244 nuclear warheads, according to SIPRI, many of which are deployed on submarines, strategic bombers, and land-based missiles. Like Russia, a significant number of these are maintained on high operational alert, capable of being launched within minutes.
China
China is the most dynamic player in the current arms race. SIPRI estimates its arsenal at over 600 nuclear warheads as of early 2025, up from roughly 500 the year before. This makes it the fastest-growing nuclear power in the world.
France
France holds around 290 nuclear warheads, a number that has remained relatively stable. But behind the scenes, it is actively investing in next-generation systems.
In 2024, France continued work on a third-generation nuclear-powered ballistic missile submarine (SSBN) and a new air-launched cruise missile, while upgrading its current ballistic missile with a new warhead modification.
United Kingdom
The United Kingdom has an estimated 225 nuclear warheads, and according to SIPRI, this number is expected to increase in the coming years. In 2024, the newly elected Labour government reaffirmed its commitment to building four new nuclear-powered ballistic missile submarines (SSBNs) as part of maintaining the UK’s continuous at-sea deterrence—a policy under which at least one submarine armed with nuclear weapons is always on patrol.
India
India now holds an estimated 172 nuclear warheads, according to SIPRI, a modest increase from previous years. However, the more significant development lies not in the number of warheads, but in technological advancements and evolving military posture.
Pakistan
Pakistan is estimated to possess around 170 nuclear warheads, and SIPRI notes that it continues to develop new missile delivery systems and produce fissile material at a steady pace—signs of a country actively expanding its arsenal despite lacking transparency or robust oversight mechanisms.
