https://currently.att.yahoo.com/news/russian-dead-casualties-ukraine-war-nato-171928734.html

This estimate, of course, includes missing, wounded, taken prisoner, etc.

If the rule of thumb is that a military unit loses full effectiveness when it absorbs >10% casualties, its no wonder the Russian offensive has bogged down. Missile and artillery barrages can be launched from well behind the lines, as can air sorties, but it appears those mechanized columns are not just waiting for supplies, many of them may be abandoned, and even intact formations cannot fulfill their missions when their support and reserve units are out of action. This 40K figure is not unreasonable when compared to earlier reports of over 10k dead.

Another factor is that the Ukrainian forces can rely on local civilian and volunteer medics, commissary, logistic, repair, transport and even engineering and construction battalions. The Russians had to bring all those people and all that stuff with them.

Militarily, this may turn into a rout for the Russians, but the Ukrainians will suffer immense civilian losses just for Putin’s spite. At the very least, this man must be declared a war criminal. He must ever be afraid to come to the West ever again, knowing he will have International warrants against him.