Russia Suffers 2nd Month of 40,000+ Casualties, 'Fails To Collapse Ukrainian Lines'

For the second month in a row, Ukrainian forces have inflicted more 

than 40,000 casualties - killed and severely wounded - on Russian troops in Ukraine. 

This means that not only is Russia unable to replace its battlefield losses with replacements of the same amount by several thousand, but the Ukrainians are getting closer to their stated goal of 50,000 Russian casualties per month, which their analysis suggests is unsustainable for the Kremlin's conduct of the war. JL

The Institute for the Study of War reports:

Russia's  Spring-Summer 2026 offensive has failed to achieve operational maneuver or rapidly collapse Ukrainian lines. Russian gains remain slow and limited. Meanwhile, Russian forces continued to suffer a high casualty rate in August 2026 for the second month in a row, paying an increasingly high price for limited battlefield gains. Russia’s current force generation system based on volunteer recruitment continues to struggle to recruit enough soldiers to replace current losses 

Russia’s Spring-Summer 2026 offensive has failed to achieve operational maneuver or rapidly collapse Ukrainian lines. Russian gains remain slow and limited. ISW has observed evidence to assess that Russian forces consolidated positions in or seized about 90.35 square kilometers of territory in Ukraine in August 2026, averaging 2.91 square kilometers seized per day. Including Russian infiltrations, Russian forces advanced or infiltrated into about 123.53 square kilometers — an average pace of 3.98 square kilometers per day. Russian forces’ main territorial gains in August 2026 have been in the Fortress Belt area, Donetsk Oblast. Even there, Russian forces managed to achieve only marginal tactical gains and have thus far failed to complete the seizure of Kostyantynivka. Russian forces maintain a presence (either through advances or infiltrations) in 72.23 percent of Kostyantynivka and have failed to completely seize the settlement, even after months of increased infiltrations and urban fighting.[1] Russian advances in August 2026 remain a fraction of Russia’s gains during the same period in 2025, even when including infiltrations. Russian forces seized 505.55 square kilometers in August 2025, for example, highlighting how Russian forces’ rate of advance continues to slow. Ukrainian forces continued counteroffensive operations across the theater in August 2026, notably in the Lyman and Oleksandrivka directions, and ISW has observed evidence to assess that Ukrainian forces liberated at least 129.81 square kilometers in August 2026.[2] This figure is very likely conservative, as ISW’s methodology underestimates the extent of likely Ukrainian gains in the ongoing counteroffensive in the Lyman direction, and additional collection will likely reveal the full extent of Ukrainian gains in the Lyman direction in Fall 2026. ISW will continue to update its assessment as more evidence becomes available.

Russian forces continued to suffer a high casualty rate in August 2026 for the second month in a row, paying an increasingly high price for limited battlefield gains. The Ukrainian General Staff reported on September 1 that Russian forces suffered 42,020 casualties in August 2026 — the second month in a row that Russian forces suffered over 40,000 casualties in a single month.[3] Russian forces suffered an average of 340 casualties per square kilometer of territory seized or infiltrated and 465 casualties per square kilometer seized in August 2026. Russia’s current force generation system based on volunteer recruitment continues to struggle to recruit enough soldiers to replace current losses, and it remains unclear how long Russian forces will be able to sustain their current footpace offensive tempo at their current loss rate without some form of mobilization