Little Boy — Hiroshima (1945) vs Fat Man — Nagasaki (1945)
The only two nuclear weapons used in war had very different designs. Little Boy (Hiroshima), a uranium gun-type device, released about 15 kt; Fat Man (Nagasaki), a plutonium implosion device, about 21 kt per the US Department of Energy, roughly 1.4 times as much. Even so, Hiroshima suffered more casualties because of each city's geography and the burst point.
Little Boy — Hiroshima (1945) · 15 kt — Fat Man — Nagasaki (1945) · 21 kt
Fat Man — Nagasaki (1945) releases 1.4 times more energy than Little Boy — Hiroshima (1945)
Fat Man — Nagasaki (1945) equals 1.4 times Hiroshima
Little Boy — Hiroshima (1945) (blue)
Fat Man — Nagasaki (1945) (red)
Blast radius scales with the cube root of energy: the larger circle is about 1.1 times wider. Relative scale only — no real distances or damage estimates.
Full scale (logarithmic)
Each step multiplies the energy; on a linear scale a grenade would vanish next to the Tsar Bomba. Tap a row to set it as B.
* Estimated, approximate or disputed figure. Yields of weapons in service are not official unless stated.
Figures used and how reliable they are
- Little Boy — Hiroshima (1945): 15 kt. Commonly cited official estimate: about 15 kt.
- Fat Man — Nagasaki (1945): 21 kt. About 21 kt per the Department of Energy.
Related comparisons
- Little Boy vs Tsar Bomba
- Beirut explosion vs Little Boy
- Halifax explosion vs Little Boy
- 155mm shell vs MOAB
Compare any other pair in the explosive yield comparison, with its full method. More context: Military history · Weapons · All tools
Sources / References
- U.S. Department of Energy, Manhattan Project history (Hiroshima and Nagasaki).
- U.S. Air Force GBU-43/B MOAB fact sheet.
- U.S. Army ammunition technical manuals (M67, M107).
- Atomic Archive and Bulletin of the Atomic Scientists (nuclear tests).