W76

USA · 1978 · 100 kilotons · thermonuclear (hydrogen bomb)

Overview

Common SLBM warhead.

With a yield of 100 kilotons, the W76 is 7× 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.

W76 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 zoneAir burstSurface burst
Fireball radius0.91 km0.73 km
Severe blast (20 PSI)2.20 km1.21 km
Moderate blast (5 PSI)4.71 km2.59 km
Light blast (1 PSI)13.39 km7.37 km
3rd-degree thermal burns4.43 km2.66 km
2nd-degree thermal burns7.93 km4.76 km
Lethal fallout zoneminimal~75.7 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 W76 on a City

Use the interactive simulator to detonate the W76 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 W76

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FAQ

How big is the W76 blast radius?

In an air burst, the W76 produces a fireball roughly 0.91 km in radius and a 5 PSI moderate-blast zone of about 4.71 km — the area in which most residential buildings would collapse. The 1 PSI light-damage radius extends to roughly 13.39 km, where windows shatter.

What is the yield of the W76?

The W76 has a yield of 100 kilotons of TNT equivalent. That is 7× more powerful than the Hiroshima bomb.

Is the W76 bigger than the Hiroshima bomb?

The Hiroshima bomb (Little Boy) had a yield of approximately 15 kilotons. The W76 at 100 kilotons is 7× more powerful than the Hiroshima bomb.

What thermal burn radius does the W76 produce?

Thermal radiation from the W76 can cause 3rd-degree burns out to roughly 4.43 km and 2nd-degree burns out to 7.93 km in an air burst. Surface bursts reduce these radii by approximately 40 percent due to ground absorption.

Sources: declassified DOE/DOD records, FAS, SIPRI, Glasstone & Dolan. See the full Weapons Database or learn about the scientific methodology.