The Center for Strategic and International Studies has published what may be the most comprehensive casualty assessment of the Ukraine war to date, estimating that Ukrainian military losses, including killed, wounded, and missing, fall between 500,000 and 600,000 from February 2022 through December 2025. Some secondary analyses place the figure slightly higher, in the range of 525,000 to 625,000.
To put that in perspective, those numbers represent one of the highest battlefield casualty rates experienced by a major military force since World War II. The CSIS report estimates Ukrainian fatalities alone at roughly 100,000 to 140,000 over the nearly four-year period.
The full picture is even grimmer
Russia has absorbed even heavier losses. The study estimates Russian military casualties at nearly 1.2 million, with fatalities ranging from 275,000 to 325,000. Combined, the two sides may have suffered up to 1.8 million casualties through the end of 2025.
That combined figure could reach 2 million by spring 2026, according to the CSIS projections. For context, the entire population of Slovenia is about 2.1 million people.
