About 352,000 Russian soldiers had died in the war against Ukraine through the end of 2025, according to a new estimate, underscoring the high cost that President Vladimir V. Putin is willing to bear to pursue his battlefield aims.

The figure was released on Saturday — the day of Russia’s annual May 9 parade celebrating victory over Germany in World War II — by the exiled Russian media outlets Meduza and Mediazona.

The number raises the prospect that about half a million soldiers in total have died on the Russian and Ukrainian sides. In the more than four years since Mr. Putin unleashed his full-scale invasion of Ukraine, the war has become Europe’s deadliest conflict since World War II.

The new estimate of Russian dead extrapolates from a database of confirmed soldier deaths that Mediazona and the BBC Russian Service have been keeping, based in part on social media posts and Russian probate records. That database now includes nearly 218,000 confirmed names.

To come up with the estimate of 352,000 deaths, Mediazona and Meduza homed in on the excess male mortality rate for younger age groups that is apparent in Russian probate records. They also made inferences about Russian deaths confirmed by courts.

The number excludes those who have died on the front this year. It also does not include the full scope of deaths among foreign fighters and soldiers who have fought for Russia in militias formed in the occupied Ukrainian territories.

The Center for Strategic and International Studies, a Washington-based think tank, estimated in January that as many as 325,000 Russian soldiers and 140,000 Ukrainian soldiers had died in the war as of the end of 2025.

Russia has moved aggressively to conceal the number of soldiers who have died, at times deleting or hiding public data that researchers can use for insight into the figures. Ukraine has put out numbers, but they are far below the estimates of Ukrainian war dead released by C.S.I.S. and other groups.

Facing an acute personnel shortage, Ukraine is seeking to ramp up the battlefield costs for Mr. Putin, with a stated aim of increasing the number of Russian soldiers killed or wounded each month to 50,000 from 30,000. According to its own statistics, Ukraine has not yet made much progress on that goal.