1. The Vietnam War cost the United States 58,000 lives and 350,000 casualties. It also resulted in between one and two million Vietnamese deaths. The amount of casualties is impossible to estimate.
http://www.digitalhistory.uh.edu/modules/vietnam/index.cfm
From Twentieth Century Atlas...
Vietnam War: Most historians of the Second Indochina War concern themselves primarily with the American Phase of the conflict, 1965-73; however, many do not specify whether their estimated death tolls cover only this phase of the war or the whole thing. An asterisk(*) indicates that the number seems to cover the entire conflict rather than just the American Phase, but check the "Sources" section to see exactly which years are covered by each authority:
South Vietnam military: 185,000 to 225,000 (Britannica) or 220,357 (Lewy) or 223,748 (Summers; also 3 April 1995 AP) or 224,000 (Kutler, Olson) or 250,000 (Clodfelter, Grenville*) or 254,257 (Wallechinsky*) or 650,000 (Small & Singer) [MEDIAN: 224,000]
North Vietnamese military and Viet Cong: 500,000 (S&S) or 660,000 (Olson) or 666,000 (Lewy, with the possibility that as many as 222,000 (1/3) of these were actually SVN civilians mistaken for VC) or 666,000 (Summers) or 700,000-1,000,000 (Wallechinsky*) or 900,000 (Britannica; Grenville*) or 1,000,000 (Clodfelter) or 1,100,000 (Tucker*, Official VN* [1954-75]) [MEDIAN: ca. 875,000]
South Vietnamese civilians: 250,000 (Olson) or 287,000 (Clodfelter = 247,600 war deaths + 38,954 assassinated by NLF) or 300,000 (Kutler; Summers) or 340,000 (Lewy's estimate, with the possibility that an additional 222,000 counted as VC (above) belong in this category) or 430,000 (The Sen. E. Kennedy Commission, according to Lewy, Olson) or 522,000 (Wallechinsky*) or 1,000,000 (Britannica [in both North and South]; Eckhardt; Grenville*) or 2,000,000 (Tucker*, Official VN* [N&S, 1954-75],) [MEDIAN: ca. 476,000]
North Vietnamese civilians: 65,000 (Kutler, Lewy, Olson, Summers, Wallechinsky) by American bombing.
USA: 58,000 (Britannica) or 58,153 (Wallechinsky*) or 58,159 (Kutler) or 47,244 KIA + 10,446 other = 57,690 (Olson, Summers, 1961-80) or 56,146 (Lewy: 46,498 KIA + 10,388 other + 719 MIA) or 56,000 (S&S)
South Korea: 4,407 (Lewy, Olson, Summers); 4,687 (Wallechinsky); 5,000 (S&S)
Philippines: 1,000 (S&S)
Thailand: 351 (Lewy, Olson, Summers, Wallechinsky); 1,000 (S&S)
Australia: 469 (Lewy, Summers, Olson [w/NZ]); 492 (S&S); 494 (Wallechinsky); 520 (AWM)
TOTAL: 1,216,000 (military only, S&S) or 1,312,000 (Summers) or 1,353,000 (Lewy) or 1,520,453 (WHPSI: S. Vietnamese only, 1965-75) or 1,637,000 (Olson) or 1,721,000 (Kutler) or 1,749,000 (Wallechinsky*) or 1,800,000 (B&J, 1960-75) or 2,058,000 (Eckhardt) or 2,163,000 (Britannica) or 2,500,000 (Grenville*) or 3,000,000 (1965-75, Chomsky* (1987)) or >3,100,000 (Tucker*; Official VN*)
[MEDIAN of TOTALS: ca. 1,900,000] or [TOTAL of MEDIANS: ca. 1,710,000]