More than two million Russian and Ukrainian troops have been killed or wounded in the four years that Russia has been waging war against its neighbor, according to a new study, a bleak milestone as Russia’s assault grinds on.
The study, published on Wednesday by the Center for Strategic and International Studies in Washington, said Russia has borne the heavier toll, with 1.4 million troops killed or wounded since February 2022, when Russia invaded Ukraine.
Of that total, 450,000 were killed, a number that is four times greater than U.S. fatalities in all wars combined since World War II.
Ukrainian forces have suffered 525,000 to 625,000 casualties, including 125,000 to 150,000 deaths, the study said.
Officials cautioned that casualty figures have been difficult to estimate throughout the war because Moscow is believed to routinely undercount its war dead and injured, and Ukraine does not disclose its official figures. The study relied on casualty figures from American and British government estimates, among other sources.
But the figures are a grim accounting of Russia’s slow progress in Ukraine, with Russian troops proceeding in some places at fewer than 165 feet a day. In February, Ukraine gained more ground than it lost for the first month since 2023 as it went on the offensive in the south, the analysts said.
“Russia’s territorial control in Ukraine shrank in the spring of 2026,” the study said. “Russian forces lost more ground than they captured in both April and May, a net loss of roughly 400 square kilometers and their first monthly net losses since August 2024 — yet another sign of Russia’s military struggles.”
Ukraine received a small assist in February when Elon Musk unexpectedly blocked Russian troops from using his satellite internet service, Starlink. That gave Ukrainian forces a brief reprieve from drone assaults and more ease of movement, analysts said.
The Russians outnumber Ukrainians on the battlefield almost three to one, and Russia has a larger population from which to replenish its ranks. So even though the study puts the number of Ukrainian troops lost at a smaller amount, Ukraine is losing a larger share of its smaller army.
More than 400,000 Russians are believed to be facing about 250,000 Ukrainians on the front line, military analysts say.
Russia has maintained its troop levels despite the high casualties by carrying out its first draft since World War II and by enlisting felons and debtors, among other tactics. President Vladimir V. Putin has paid bounties to new recruits and has pressed people accused of crimes to enlist in exchange for dismissing charges.
In addition, in 2024 and 2025 North Korea sent more than 10,000 soldiers to help Russia take back its western Kursk region, where Ukraine had captured territory.
The study said that in 2026, Russia’s monthly casualty rates of 30,000 to 34,000 probably exceeded its recruitment rates of about 27,000 new recruits per month.
The report comes as President Trump has largely disengaged from the war in Ukraine. At a summit in France last month, Mr. Trump made clear that the conflict, which he once said he could end in 24 hours, was not among his priorities.
“Look, we have nothing to do with it,” Mr. Trump said, adding, “It has no impact on us, other than we sell weapons” to Ukraine.
His remarks underscored a new security reality for U.S. allies in Europe, who for eight decades relied on American protection until the Trump administration made it clear that protection was a thing of the past.
Mr. Trump cast U.S. involvement in Ukraine more as a humanitarian mission than as an effort to protect an ally, citing the number of casualties in both Ukraine and Russia as the reason he wanted to bring the war to a close.
Ukraine’s supporters, including those in Congress, have said that preventing Russia from winning the war was also necessary to prevent an emboldened Mr. Putin from attacking other NATO allies.
Ukraine is likely to be discussed at a NATO summit on Tuesday in Ankara, Turkey.
The study said that without more U.S. and European pressure on Russia, Mr. Putin will continue his war, despite the heavy losses.
The study noted that Ukraine has taken more of the war to Russia through the use of drones and missiles and an increasingly effective air campaign.
Last month, Ukraine launched its biggest drone assault on Moscow since the start of the war.
And this week, Ukraine launched more drone attacks, including on the capital and in Crimea, the peninsula Moscow annexed from Ukraine in 2014. Overall, Russia shot down 419 drones, the Russian Defense Ministry said in a statement.
“Russia is facing, by far, its darkest period of the war since its February 2022 invasion of Ukraine,” said Seth G. Jones, one of the authors of the study. “The war has come home to everyday Russians, who are paying the price of President Putin’s war with a sputtering economy, skyrocketing prices, a growing number of body bags coming back from the front lines and drone strikes in Russian cities.”
