Lend-Lease support to the Soviets was extremely important, particularly mid to late war. While the Soviets would have most likely stopped the German advance at Moscow and Stalingrad, they would not have been able to sustain a prolonged advance back into Germany without Lend-Lease aid.

Food – The German advance across Ukraine meant the loss of nearly 40% of agricultural production and the loss of nearly 100 million head of cattle, pigs, sheep and goats. The remaining agricultural areas also suffered as their horses and tractors were taken to help with the war effort. The US helped feed the Soviet Union during the war by supplying one million tons of cereal products, 787 thousand tons of meat product, 625 thousand tons of animal fat, 465 thousand tons of vegetable fat, 624 thousand tons of sugar, and 330 thousand tons of concentrate (milk and eggs.) Until Japan entered the war, non-military goods could be shipped across the Pacific, rather than the much more dangerous northern route or longer route through the middle east.

Transportation – The US also provided 34,000 motorcycles, 45,000 jeeps, 78,000 light trucks(1-ton and under), 151,000 medium trucks (1-2&1/2 ton), 200,000 medium-heavy trucks (2&1/2 ton), and 2,000 heavy trucks (over 2&1/2 ton.) They also provided nearly half of the rails used to build and repair railroads along with supplying 2,000 locomotives and 10,000 flat cars.

Raw Materials – Most of the steel and aluminum production in the Soviet Union was in Ukraine and had been overrun by the Germans. Western Allies would supply the Soviets 85% of their aluminum, 76% of their copper, and 33% of their steel throughout the war, along with thousands of tons of other vital ferrous and non-ferrous materials. Most was provided as finished products or ready for manufacturing such as rolled steel or nearly a million miles of telephone cable. The US would also supply nearly 2/3 of the Soviets aviation fuel during the war, as US refineries were able to produce higher octane gasoline in larger quantities.

Weapons, etc. – The Soviets manufactured most of their own weapons but lend-lease was important. By the end of 1944, the allies had supplied 12,000 aircraft (4 out of the top 6 Soviet aces had the majority of their kills while flying the US P-39 Airacobra), 137,000 machine guns, 6,000 tanks (British tanks were especially critical in the defense of Moscow), 1,800 self-propelled guns, 13,000 pistols, 3,300 armored personnel carriers, 8,200 field and antitank guns 5,500 artillery tractors. The Allies also supplied over 4 million artillery rounds, 11 million anti-aircraft rounds, 150 million feet of blasting fuse, 49,000 bundles of perforated steel plate for runways, 4 million lbs. of smoke, incendiary and white phosphorus chemicals, 11 million pairs of boots, 97 million yards of cotton fabric, and 50 million yards of woolen goods.

It’s hard to quantify how important lend-lease was to the Soviets, but the amount of materials was massive, and things such as food, trucks, rails, aluminum, copper, steel and aviation fuel were undoubtedly vital to the Soviet war effort.

Sources

Nikolay Ryzhkov & Georgy Kumanev “Food and other strategic deliveries to the Soviet Union under the Lend-Lease Act, 1941-1945”

Chief of Military History “United States Army in World War II Statistics: Lend-Lease”