B83
USA · 1983 · 1.2 megatons · thermonuclear (hydrogen bomb)
Overview
Most powerful US weapon still in the stockpile (retirement pending).
With a yield of 1.2 megatons[1, 2], the B83 is 80× more powerful than the Hiroshima bomb. As a thermonuclear (hydrogen bomb) weapon, it derives its energy from a fission explosion that ignites fusion fuel, releasing on average roughly equal energy from fission and fusion. [3]
B83 Blast Effects
The table below shows the calculated radius of each effect zone for an air burst at optimum height. Values are scaling laws from The Effects of Nuclear Weapons (Glasstone & Dolan, 1977) and the published effects scaling table[4, 5].
| Effect zone | Radius (air burst) |
|---|---|
| Fireball radius | 1.04 km |
| Severe blast (20 psi) | 2.55 km |
| Moderate blast (5 psi) | 6.59 km |
| Light blast (1 psi) | 18.1 km |
| 3rd-degree thermal burns | 12.9 km |
| 2nd-degree thermal burns | 16.0 km |
| 1st-degree thermal burns | 20.2 km |
All radii assume an air burst at optimum height and are 1-D ground-distance estimates from the detonation point. Real-world effects depend on terrain, weather, and building construction. Casualty and fallout estimates are not shown pending a verified population and fallout model.
Run the B83 on a City
Use the interactive simulator to detonate the B83 on any city worldwide. Click any location on the map to see the fireball, blast, and thermal radii (air burst at optimum height) overlaid on real geography.
🎯 Simulate B83Related Weapons
FAQ
How big is the B83 blast radius?
In an air burst at optimum height, the B83 produces a fireball roughly 1.04 km in radius and a 5 psi moderate-blast zone of about 6.59 km — the area in which most residential buildings would collapse. The 1 psi light-damage radius extends to roughly 18.1 km, where windows shatter.
What is the yield of the B83?
The B83 has a yield of 1.2 megatons of TNT equivalent. That is 80× more powerful than the Hiroshima bomb.
Is the B83 bigger than the Hiroshima bomb?
The Hiroshima bomb (Little Boy) had a yield of approximately 15 kilotons. The B83 at 1.2 megatons is 80× more powerful than the Hiroshima bomb.[6]
What thermal burn radius does the B83 produce?
In an air burst at optimum height, thermal radiation from the B83 can cause 3rd-degree burns out to roughly 12.9 km, 2nd-degree burns to 16.0 km, and 1st-degree burns to 20.2 km.
Sources
- 1.Source: Bulletin of the Atomic Scientists / FAS (Kristensen, Korda, Johns, Knight-Boyle), United States nuclear weapons, 2026 (Nuclear Notebook, 12 Mar 2026) — retrieved Oct 2026
- 2.Source: Nuclear Weapon Archive (Carey Sublette), Complete List of All U.S. Nuclear Weapons (last changed 30 Mar 2023) — retrieved Oct 2026
- 3.Source: US DoD & ERDA (Glasstone & Dolan), via Atomic Archive, The Effects of Nuclear Weapons, 3rd ed. (1977), Chapter 1 — retrieved Oct 2026
- 4.Source: U.S. DoD / DOE (Glasstone & Dolan, via Atomic Archive), The Effects of Nuclear Weapons, 3rd ed. (1977) §2.127 — retrieved Oct 2026
- 5.Source: Wikipedia, Effects of nuclear explosions — scaling-law table — retrieved Oct 2026
- 6.Source: US DOE / NNSA Nevada Field Office, United States Nuclear Tests, July 1945 through September 1992 (DOE/NV-209 Rev. 16, Sep 2015), NNSS publication library — retrieved Oct 2026