B83 vs B53
Nuclear weapon side-by-side comparison
B83
USA · 1983 · thermonuclear
1.2 Mt
Most powerful US weapon in active service.
B53
USA · 1962 · thermonuclear
9 Mt
Retired high-yield bomb.
Verdict
The B53 is 7.5× more powerful than the B83 by yield. Both weapons are described in detail below, with side-by-side blast and thermal radii, casualty estimates at a reference urban density, and historical context.
Blast & thermal effects (air burst)
| Effect zone | B83 | B53 |
|---|---|---|
| Yield | 1.2 Mt | 9 Mt |
| Fireball radius | 2.47 km | 5.53 km |
| Severe blast (20 PSI) | 5.00 km | 9.73 km |
| Moderate blast (5 PSI) | 10.69 km | 20.78 km |
| Light blast (1 PSI) | 30.41 km | 59.12 km |
| 3rd-degree thermal burns | 12.26 km | 28.01 km |
| 2nd-degree thermal burns | 21.96 km | 50.17 km |
Casualty estimate (dense urban target)
Estimated immediate fatalities if each weapon air-bursts over a city center with a population density of about 8,000 per km² (representative of dense urban cores like Manhattan or central Paris):
Real casualties depend strongly on time of day, sheltering, weather, and altitude of detonation. See the methodology page for the underlying formulas.
Hiroshima reference
The Hiroshima bomb (Little Boy) had a yield of approximately 15 kilotons. The B83 is 80× more powerful than the Hiroshima bomb. The B53 is 600× more powerful.
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FAQ
Is the B83 bigger than the B53?
No. The B53 (9 Mt) is 7.5× more powerful than the B83 (1.2 Mt).
What is the blast radius of the B83 compared to the B53?
For an air burst, the B83 produces a 5 PSI moderate-blast radius of 10.69 km, versus 20.78 km for the B53. Severe blast (20 PSI): 5.00 km vs 9.73 km. 3rd-degree thermal burns: 12.26 km vs 28.01 km.
How many people would die from a B83 compared to a B53?
Detonated over a typical dense city center (8,000 people/km²), the B83 would cause an estimated 1,737,845 immediate fatalities. The B53 would cause an estimated 6,569,792. Real numbers depend on time of day, sheltering, weather, and altitude of detonation.
How do the B83 and B53 compare to the Hiroshima bomb?
The B83 is 80× more powerful than the Hiroshima bomb (Little Boy, 15 kt). The B53 is 600× more powerful than the Hiroshima bomb.