How Far Away Do You Need to Be to Survive a Nuclear Bomb?

In the heart of a nuclear explosion, the human body doesn’t burn—it vaporizes. Bone turns to dust. Air becomes a weapon. If you’re close enough, you don’t scream. You don’t run. You’re just…gone.

That’s not an exaggeration. That’s physics. And in a recent modeling exercise by AsapSCIENCE, researchers analyzed what would happen if a 1-megaton nuclear bomb—roughly 80 times more powerful than the one dropped on Hiroshima—were detonated. They also tried to answer the question nobody wants to ask: how far would you need to be to survive?

At ground zero, temperatures can reach 100 million degrees Celsius. That’s hotter than the core of the Sun. Anyone nearby would be reduced to carbon instantly. But even far beyond the epicenter, the effects are catastrophic. Third-degree burns—where skin blisters and nerves are destroyed—can hit anyone within 8 kilometers (5 mi.). First-degree burns can reach 11 kilometers (7 mi.), depending on weather and clothing.

How to Survive a Nuclear Blast

Light travels even faster than heat. On a clear day, people up to 21 kilometers (13 mi.) away could experience flash blindness. At night, that range increases to 85 kilometers (53 mi.) due to pupil dilation. You wouldn’t need to see the blast to be affected by it.

The shockwave isn’t any kinder. Within a 6-kilometer (3.7 mi.) radius, wind speeds can exceed 255 kilometers per hour (158 mph), strong enough to flatten buildings and rip people off their feet. Closer in, speeds approach 750 kilometers per hour (466 mph), and air pressure is enough to crush most structures. Even if you’re technically far enough to survive the heat, flying debris or collapsing buildings could still kill you.

And then comes the radiation. Fallout from a ground-level detonation can spread toxic particles for hundreds of miles, contaminating soil, air, and water. Traces of Cold War nuclear tests have been found in the Mariana Trench. That’s how far this stuff travels.

If you’re lucky enough to be more than 30 to 40 kilometers (18–25 mi.) away, indoors, and upwind from the blast, you might survive the initial impact. But that’s just the beginning. A 2019 simulation found that a large-scale nuclear war could trigger a planet-wide nuclear winter in a matter of days.

There are more than 12,000 nuclear warheads still on Earth. So no, this isn’t just academic. If something goes off, being far away won’t make you safe. But it might buy you a little time.