When the news broke in April 2017 that the United States had dropped the "Mother of All Bombs" on an ISIS-K tunnel complex in eastern Afghanistan, the internet basically exploded. People were sharing CGI renders and clips of massive mushroom clouds, making it look like a tactical nuke had gone off. But if you're asking how big is the moab bomb, the answer is actually more about the physics of "air blast" than just a giant crater in the dirt.
Honestly, the MOAB is a bit of a weirdo in the munitions world. It’s officially the GBU-43/B Massive Ordnance Air Blast. It isn’t designed to "punch" through the ground like a bunker buster. Instead, it’s meant to create a massive wall of pressure that turns everything in its path into dust.
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The Absolute Units: Dimensions and Weight
Let’s talk raw numbers because they’re kinda terrifying. The MOAB is about 30 feet long. That’s roughly the length of a standard school bus or three mid-sized sedans parked bumper-to-bumper. It’s about 40 inches in diameter, which doesn't sound like much until you realize that’s over three feet of solid explosive girth.
The weight is where things get truly ridiculous. It clocks in at 21,600 pounds.
To put that into perspective, a standard JDAM (Joint Direct Attack Munition) that you see under the wing of an F-16 usually weighs about 500 to 2,000 pounds. You’d need at least ten of those to equal the weight of a single MOAB. Out of that 21,600-pound total weight, 18,700 pounds is the actual explosive filler—a cocktail called H-6.
H-6 is basically TNT on steroids. It’s a mix of RDX, TNT, and aluminum powder. The aluminum is key because it makes the explosion last longer and burn hotter.
It Doesn't Even Fit on a Bomber
One of the most surprising things about how big the MOAB bomb is involves how it gets into the air. Most people imagine a B-2 Spirit stealth bomber or a B-52 Stratofortress carrying this thing. Nope. It’s way too big for their internal bomb bays.
Instead, the Air Force has to use a C-130 Hercules—a cargo plane.
Basically, they put the bomb on a wooden cradle, slide it into the back of the cargo hold, and then pull it out the back door with a parachute. Once it clears the plane, the cradle falls away, and the bomb’s internal GPS system takes over. It uses those weird-looking "lattice fins" on the back to steer itself toward the target.
If you’ve ever seen a picture of it, it looks like a giant green cigar with honeycombs on the tail. Those fins are actually high-tech aero-grids that help it stay stable without needing a massive wingspan.
The Blast Radius: A Mile of "No Thanks"
So, how big is the explosion? This is where the "Air Blast" part of the name comes in. The MOAB is an air-burst weapon. It doesn't wait to hit the ground; it detonates about six feet above the surface.
This is a tactical choice. If a bomb hits the ground before exploding, a lot of that energy gets absorbed by the dirt or reflected upward. By exploding in the air, the pressure wave can travel horizontally for huge distances.
- The Primary Blast: The shockwave has a radius of about one mile.
- The Overpressure: Within several hundred yards of the center, the air pressure is so high it can literally collapse human lungs and cave in reinforced tunnels.
- The Fireball: While it isn't "thermobaric" in the strictest chemical sense, the massive amount of aluminum powder in the H-6 creates a sustained, intense heat that sucks the oxygen out of enclosed spaces like caves.
In that 2017 strike in Nangarhar, the bomb was used specifically because ISIS-K fighters were hiding in deep tunnels. The MOAB didn't need to hit them directly; it just needed to send a wall of high-pressure air into the tunnel entrances to collapse them from the inside out.
How Big is the MOAB Bomb Compared to a Nuke?
This is the biggest misconception out there. People love to say the MOAB is "basically a small nuke."
It’s not. Not even close.
The MOAB has an explosive yield of about 11 tons of TNT. The smallest nuclear weapon ever produced by the U.S., the "Davy Crockett" warhead from the Cold War, had a yield of about 10 to 20 tons. So, okay, in that one specific case, they're comparable.
But look at the "Little Boy" bomb dropped on Hiroshima. That was about 15,000 tons (15 kilotons). That means the Hiroshima bomb was 1,300 times more powerful than the MOAB. Modern nukes are even crazier, often measured in megatons. The MOAB is the "Mother of All Bombs" in the conventional world, but in the nuclear world, it’s a firecracker.
Why We Rarely Use It
The U.S. only has about 15 to 20 of these things in inventory. They cost roughly $170,000 to $314,000 each, depending on how you calculate the R&D costs. They aren't exactly "mass-produced."
The main reason they stay in the hangar is that they're hard to use safely. You can’t drop a MOAB if there are any civilians within a few miles. You also can't drop it if the enemy has any decent anti-aircraft missiles, because a C-130 is basically a flying bus—it's slow, loud, and an easy target.
It’s a "psychological warfare" tool as much as a physical one. When you drop something that big, the whole mountain range feels it.
Actionable Takeaways for History and Tech Buffs
If you're researching the MOAB for a project or just want to win an argument, remember these key distinctions:
- Size matters, but casing doesn't: Unlike the "Grand Slam" bombs of WWII, which had thick steel walls to penetrate the ground, the MOAB has a thin aluminum skin. This allows it to carry more explosives for its weight.
- GPS is the secret sauce: Older giant bombs like the "Daisy Cutter" were unguided. The MOAB is a precision instrument, despite its size.
- Check the carrier: If someone says a fighter jet dropped a MOAB, they're wrong. It’s strictly a cargo-plane job.
- The "Father" Comparison: Russia claims they have a "Father of All Bombs" (FOAB) that is four times more powerful than the MOAB, but there is zero independent verification that it actually works as advertised.
The MOAB remains the largest non-nuclear weapon ever used in combat. It sits in a very narrow niche of military technology: too big for a normal war, too small for a nuclear one, but just right for clearing out a mountain.