Nuke Blast Simulator

Tsar Bomba vs Castle Bravo

Nuclear weapon side-by-side comparison

By Marko Visic, BSc Physics

Tsar Bomba

USSR · 1961 · thermonuclear

50 megatons

Largest nuclear weapon ever tested. [1]

Castle Bravo

USA · 1954 · thermonuclear

15 megatons

Most powerful US nuclear test. [2]

Verdict

The Tsar Bomba is 3.3× more powerful than the Castle Bravo by yield. Both weapons are detailed below, with side-by-side blast and thermal radii for an air burst.

Blast & thermal radii (air burst)

Effect zoneTsar BombaCastle Bravo
Yield50 megatons15 megatons
Fireball radius4.62 km2.86 km
Severe blast (20 psi)8.64 km5.82 km
Moderate blast (5 psi)23.1 km15.4 km
Light blast (1 psi)64.1 km42.6 km
3rd-degree thermal burns54.1 km34.0 km
2nd-degree thermal burns61.2 km39.7 km

Air burst at optimum height, computed by the site's effects engine. [3, 4] Casualty and fallout estimates are withdrawn pending a verified model.

Hiroshima reference

The Hiroshima bomb (Little Boy) had a yield of approximately 15 kilotons. [2] The Tsar Bomba is 3,333× more powerful than the Hiroshima bomb. The Castle Bravo is 1,000× more powerful than the Hiroshima bomb.

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FAQ

Is the Tsar Bomba bigger than the Castle Bravo?

Yes. The Tsar Bomba (50 megatons) is 3.3× more powerful than the Castle Bravo (15 megatons) by yield.

What is the blast radius of the Tsar Bomba compared to the Castle Bravo?

For an air burst at optimum height, the Tsar Bomba produces a 5 psi moderate-blast radius of 23.1 km, versus 15.4 km for the Castle Bravo. Severe blast (20 psi): 8.64 km vs 5.82 km. 3rd-degree thermal burns: 54.1 km vs 34.0 km.

How do the Tsar Bomba and Castle Bravo compare to the Hiroshima bomb?

The Hiroshima bomb (Little Boy) was about 15 kt. The Tsar Bomba is 3,333× more powerful than the Hiroshima bomb. The Castle Bravo is 1,000× more powerful than the Hiroshima bomb.

Sources

  1. 1.Source: Nuclear Weapon Archive (Carey Sublette), Soviet Atmospheric Tests (last updated 7 Oct 1997) — retrieved Oct 2026
  2. 2.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
  3. 3.Source: U.S. DoD / DOE (Glasstone & Dolan, via Atomic Archive), The Effects of Nuclear Weapons, 3rd ed. (1977) §2.127 — retrieved Oct 2026
  4. 4.Source: Wikipedia, Effects of nuclear explosions — scaling-law table — retrieved Oct 2026
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