Though ultimately victorious, the American victory at Iwo Jima had been extremely costly. According to the Navy Department Library, "the 36-day assault resulted in more than 26,000 American casualties, including 6,800 dead." By comparison, the much larger scale 82-day Battle of Okinawa lasting from early April until mid-June 1945 (involving five U.S. Army and two Marine Corps divisions) resulted in over 62,000 U.S. casualties, of whom over 12,000 were killed or missing. Iwo Jima was also the only U.S. Marine battle where the American casualties exceeded the Japanese

The USS Bismarck Sea was lost, the last U.S. aircraft carrier sunk in World War II. 20 Grumman FM-2 Wildcat fighters and 11 Grumman TBM Avenger torpedo bombers went down with Bismarck Sea. Also, the USS Saratoga was so severely damaged that she no longer took part in either combat or transportation duties for the rest of the war. She became a training ship. 31 Grumman F6F Hellcat fighters and 9 Grumman TBM Avenger torpedo bombers were destroyed by the kamikaze attack on Saratoga. Because all civilians had been evacuated, there were no civilian casualties at Iwo Jima, unlike at Saipan and Okinawa.