After the German 6th Army was encircled in the Battle of Stalingrad, Göring convinced Hitler to resupply the besieged forces by airlift until a relief effort could reach them; however, the sheer scale of the effort required in Stalingrad (calculated at 750 tons per day) greatly exceeded the Luftwaffe's now-depleted capacities. The Stalingrad airlift effort ultimately failed to deliver sufficient supplies, and the Germans estimated that they lost 488 transports, as well as 1,000 personnel, to the now-strengthened Soviet Air Forces. Despite the Stalingrad airlift, the German 6th Army, counting 300,000 soldiers trapped in the city, had to surrender in February 1943, due to their degrading physical condition, as the supplies with food, new troops, weapons and ammunition was not sufficient to defeat the Soviet troops at Stalingrad. At the time of the surrender, the German 6th Army lost 100,000 soldiers at Stalingrad, counting from November 1942 until February 1943.