Overview

• An estimated 12,241 nuclear warheads were in existence as of January 2025, marking a halt to decades of post-Cold War reductions.
• China added roughly 100 warheads between 2023 and 2024 to reach about 600, making it the fastest-growing arsenal among the nine nuclear-armed states.
• The United States and Russia account for roughly 90 percent of global warheads and their New START treaty expires in February 2026, potentially removing limits on deployed arsenals.
• India expanded its arsenal to about 180 warheads and Pakistan to around 170, with both countries advancing new missile and submarine-based delivery systems.
• Nuclear doctrines are being reshaped by artificial intelligence, cyber capabilities and space-based assets, complicating verification and raising risks of inadvertent conflict.