What nation suffered the highest amount of casualties in World War 2?

Answer 1

That would be the Soviet Union (Russia).

The Russian losses were so high because of both the Nazis and the Russian leaders themselves. There are reports of Russian pilots being ordered to crash into German bombers when they ran out of ammunition (bear in mind pilots are difficult and expensive to train). And at least one report of Russian troops being ordered by their own leaders to clear a minefield by marching across it. Russian military leaders often lacked proper planning and strategy in military operations, leading to high losses on the battlefields against Germany.
The Russians also failed to protect civilians who were not even near warzones by failing to supply them with essentials, leading to millions of Russian civilians to die of famine. The Russians also reportedly murdered innocent German civilians as they marched on Berlin.
The Russian military leaders were just as bad and barbaric as the Nazis.


The top 10 losses are:

1. Soviet Union (Russia). Between 25,000,000 to 30,000,000 casualties.
2. China. Between 15,000,000 to 20,000,000 casualties.
   
3. Germany. Between 7,000,000 to 9,000,000.
4. Poland. Between 5,000,000 to 6,000,000 casualties.
5. Dutch East Indies. Between 3,000,000 to 4,000,000 casualties.
6. Japan. Between 2,500,000 to 3,000,000 casualties.
7. India (under British rule). Between 1,587,000 to 2,587,000 casualties.
8. Yugoslavia. Between 1,000,000 to 1,700,000 casualties.
9. French Indochina. Between 1,000,000 to 2,200,000 casualties.
10. Romania. Around 800,000 casualties.

You can see more information on the casualties by clicking here.