The history of nuclear weapons is a story of extremes, and the largest bombs ever built are among the most extreme examples of human ingenuity and destruction.
Only two nuclear bombs have ever been deployed against humans, both in the United States’ bombing campaign against Japan to conclude World War II.
Just one 13 kiloton yield nuclear bomb dropped on Hiroshima nicknamed “Little Boy” incinerated nearly 100,000 people, while the 21 kiloton yield bomb deployed against Nagasaki (“Fat Man”) killed over 70,000.1
These megaton-class devices were thousands of times more powerful than the bombs used against Japan and were designed to unleash a level of devastation never before seen on Earth. Their development marked a new era in the arms race between superpowers.
From the infamous Tsar Bomba of the Soviet Union to the lesser-known but no less powerful Castle Bravo of the United States, this article takes a deep dive into the history of the largest nuclear bombs ever built.
5 Largest Nuclear Bombs by Yield
The 5 largest nuclear bombs ever built (by yield) include:
- Tsar Bomba (~50 megatons)
- B41 (~25 megatons)
- TX-21 “Shrimp” (~15 megatons)
- MK-17/EC-17 (~10-15 megatons)
- MK-24/B-24 (~10-15 megatons)
All of the 5 largest nuclear bombs ever built would cause considerably more death and destruction than those first ones used against Japan. According to world renowned nuclear researcher Jozef Goldblat, a nuclear explosion the size of 10-20 megatons in a city such as New York would lead to casualties in excess of 5 million (based on 1981 population figures).2
The largest nuclear bomb ever built by far has been the Soviet produced Tsar Bomba. The test blast of the devastating weapon reportedly broke windows over 560 miles away.
The B41 was the largest US nuclear weapon ever made with a projected 25 megaton payload, though it was never tested. The B41 remained in service for a several decades before its retirement in 1976.
The TX-21 “Shrimp” was the largest US weapon ever tested. The infamous Castle Bravo test at Bikini Atoll in the Marshall Islands utilized the TX-21, the subject of which led to much international scrutiny over the fallout and radiation levels.
The last two bombs (MK-17 and MK-24) were identical in appearance and their payloads. The only difference was the design of their primary section. These bombs were very large and the heaviest nuclear weapons the US ever built and put into service.
While the arms race during the Cold War saw thousands of nuclear warheads built and jettisoned around the world, fortunately none have ever been used again.
To learn more about US history, check out this timeline of the history of the United States.
1) York, Herbert. “The Nuclear ‘Balance of Terror’ in Europe.” Ambio, vol. 4, no. 5/6, 1975, pp. 203–08. JSTOR, http://www.jstor.org/stable/4312147.
2) Goldblat, Jozef. “Nuclear Weapons — The Threat to Our Survival.” Bulletin of Peace Proposals, vol. 12, no. 1, 1981, pp. 30–32. JSTOR, http://www.jstor.org/stable/44480911.