The 25 largest militaries in the world, ranked by active troops

"Active-duty force size is a tally of a country's uniformed troops: airmen, soldiers, sailors, special operators, and Marines. Armies, in particular, depend on size to gain and occupy ground. Militaries can also be a tool of domestic repression, a focus that undercuts its capabilities against an external foe. North Korea, for example, is one of the world's most repressive states, led by a dictator who has repeatedly threatened neighboring South Korea."

"While theUS military has pursued ambitious technological advances, manpower remains one of its core pillars. From high-ranking generals to soldiers on the field, human troops remain a key way to assess the reach and power of the world's militaries. Using data from the International Institute for Strategic Studies' 2025 Military Balance report, Business Insider ranked countries by the size of their active armed forces and listed their defense budgets, based on 2024 figures."

"The number of active-duty military personnel is far from the only factor that matters when comparing military power between countries, but it shows latent power that could be augmented via conscription and calling up reservists. "Numbers have value, but there's a lot more to military capability," said Mark Cancian, a senior adviser at the Center for Strategic and International Studies, a Washington, DC-based foreign policy and national security think tank."

Data from the International Institute for Strategic Studies' 2025 Military Balance ranks countries by active armed forces and lists defense budgets based on 2024 figures. China, India, and the United States have the largest active-duty militaries. The world's top armies spend hundreds of billions of dollars on defense annually. Active-duty force size counts uniformed troops: airmen, soldiers, sailors, special operators, and Marines. Armies rely on size to gain and occupy ground. Militaries can also serve domestic repression, which undercuts external capabilities; North Korea exemplifies this risk. Reservists and paramilitaries expand latent power; Vietnam has an estimated 5 million reservists.

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