B41
USA · 1960 · 25 megatons · thermonuclear (hydrogen bomb)
Overview
Most powerful US bomb ever deployed.
With a yield of 25 megatons, the B41 is 1,667× more powerful than the Hiroshima bomb. As a thermonuclear (hydrogen bomb) weapon, it derives its energy from a fission primary that ignites a much larger fusion secondary stage.
B41 Blast Effects
The table below shows the calculated radius of each effect zone for an air burst (optimal altitude, maximum blast spread) and a surface burst (ground level, with massive radioactive fallout). Formulas are scaling laws from The Effects of Nuclear Weapons (Glasstone & Dolan, 1977).
| Effect zone | Air burst | Surface burst |
|---|---|---|
| Fireball radius | 8.33 km | 6.66 km |
| Severe blast (20 PSI) | 13.63 km | 7.49 km |
| Moderate blast (5 PSI) | 29.12 km | 16.01 km |
| Light blast (1 PSI) | 82.83 km | 45.56 km |
| 3rd-degree thermal burns | 42.58 km | 25.55 km |
| 2nd-degree thermal burns | 76.27 km | 45.76 km |
| Lethal fallout zone | minimal | ~689.2 km |
All values are 1-D ground-distance estimates from the detonation point. Real-world effects depend on terrain, weather, and building construction.
Run the B41 on a City
Use the interactive simulator to detonate the B41 on any city worldwide. Click any location on the map to see the fireball, blast, and thermal radii overlaid on real geography with population-density-based casualty estimates.
🎯 Simulate B41Related Weapons
FAQ
How big is the B41 blast radius?
In an air burst, the B41 produces a fireball roughly 8.33 km in radius and a 5 PSI moderate-blast zone of about 29.12 km — the area in which most residential buildings would collapse. The 1 PSI light-damage radius extends to roughly 82.83 km, where windows shatter.
What is the yield of the B41?
The B41 has a yield of 25 megatons of TNT equivalent. That is 1,667× more powerful than the Hiroshima bomb.
Is the B41 bigger than the Hiroshima bomb?
The Hiroshima bomb (Little Boy) had a yield of approximately 15 kilotons. The B41 at 25 megatons is 1,667× more powerful than the Hiroshima bomb.
What thermal burn radius does the B41 produce?
Thermal radiation from the B41 can cause 3rd-degree burns out to roughly 42.58 km and 2nd-degree burns out to 76.27 km in an air burst. Surface bursts reduce these radii by approximately 40 percent due to ground absorption.