Halifax explosion (1917) vs Little Boy — Hiroshima (1945)
In 1917 the collision of a munitions ship in the Canadian port of Halifax caused an explosion of about 2.9 kt, the largest accidental blast before the atomic age. Little Boy (about 15 kt) was roughly five times larger. For decades Halifax was cited as the benchmark for what a single explosion could do to a city.
Halifax explosion (1917) · 2.9 kt — Little Boy — Hiroshima (1945) · 15 kt
Little Boy — Hiroshima (1945) releases 5.2 times more energy than Halifax explosion (1917)
Little Boy — Hiroshima (1945) equals 1 times Hiroshima
Halifax explosion (1917) (blue)
Little Boy — Hiroshima (1945) (red)
Blast radius scales with the cube root of energy: the larger circle is about 1.7 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
- Halifax explosion (1917): 2.9 kt. Munitions ship collision; largest pre-atomic accidental blast.
- Little Boy — Hiroshima (1945): 15 kt. Commonly cited official estimate: about 15 kt.
Related comparisons
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).