User blog comment:NovaSims/What WW2 have been like if Hitler adnt attacked Russia and Japan hadnt attacked America?/@comment-4621372-20120909190549/@comment-4621372-20120909210229

" I thinkest not. That's around 70,000- 100,000 Americans. WAY less than the bombings. And all of those would have been soldiers. Those were people who signed up. True, if you count the Japanese dead, it might edge the total from the bombings. Note, 'might', 'edge'. Radiation would cause HUGE deaths.
 * A study done by Adm. Nimitz's staff in May estimated 49,000 U.S casualties in the first 30 days, including 5,000 at sea.[43] A study done by General MacArthur's staff in June estimated 23,000 US casualties in the first 30 days and 125,000 after 120 days.[44] When these figures were questioned by General Marshall, MacArthur submitted a revised estimate of 105,000, in part by deducting wounded men able to return to duty.[45]
 * In a conference with President Truman on June 18, Marshall, taking the Battle of Luzon as the best model for Olympic, thought the Americans would suffer 31,000 casualties in the first 30 days (and ultimately 20% of Japanese casualties, which implied a total of 70,000 casualties).[46] Adm. Leahy, more impressed by the Battle of Okinawa, thought the American forces would suffer a 35% casualty rate (implying an ultimate toll of 268,000).[47] Admiral King thought that casualties in the first 30 days would fall between Luzon and Okinawa, i.e., between 31,000 and 41,000.[47] Of these estimates, only Nimitz's included losses of the forces at sea, though kamikazes had inflicted 1.78 fatalities per kamikaze pilot in the Battle of Okinawa,[48] and troop transports off Kyūshū would have been much more exposed."

BUt, moot point! The Japanese couldn't withstand a combined US- USSR attack, with British troops helping. Those totals are for an American only assault. 100,000, if you count those who could return to combat. NOw, with the British and Soviets helping!