Here’s how big our nuclear arsenal is 80 years after the first atomic bomb
Atomic arsenal
The 80th anniversary of the atomic bombing of Hiroshima and Nagasaki is this week. It was the only time nuclear warheads were used during war. Here’s a look at the history and current U.S. stockpile.
More deadly: Today’s nuclear weapons can be far more devastating than the horror that happened at Hiroshima on Aug. 6, 1945.
The circles above show the blast radius of the Hiroshima atomic bomb compared with a modern hydrogen bomb.
The Hiroshima bomb, nicknamed Little Boy, was air burst 1,900 feet above the city to maximize destruction; it was later estimated to yield 15 kilotons. Two-thirds of the city area was destroyed. The population present at the time was estimated at 350,000, and 140,000 died by the explosion and its radiation.
In the current U.S. nuclear arsenal, the W88 warheads deployed on Trident II submarine-launched missiles have an estimated yield of 475 kilotons.
U.S. nuclear warheads
The United States has embarked on a wide-ranging nuclear modernization program that will ultimately see every nuclear delivery system replaced with newer versions over the coming decades.
According to the Bulletin of the Atomic Scientists, the U.S. maintains a stockpile of approximately 3,708 warheads — an unchanged estimate from the previous year. Of these, only about 1,770 warheads are deployed, while approximately 1,938 are held in reserve.
Approximately 1,336 retired warheads are awaiting dismantlement, giving a total inventory of approximately 5,044 nuclear warheads.
Of the approximately 1,770 warheads that are deployed, 400 are on land-based intercontinental ballistic missiles.
See also: 80th anniversary: A look at the memorials in Hiroshima and Nagasaki
These nuclear-tipped missiles are stationed underground in Colorado, Wyoming, Montana, Nebraska and North Dakota. They’re staffed around the clock and kept on hair-trigger alert.
Roughly 970 are submarine-launched ballistic missiles.
300 are at bomber bases in the United States
Approximately 100 tactical bombs are at European bases.
Aircraft arsenal
About 300 bombs and air-launched cruise missiles are deployed on air bases in the United States. Another 100 bombs are in Europe. All are capable of smaller, lower-yield explosions, which may increase the risk that they’ll actually be used.
Submarine arsenal
Assuming an average of 12 operational submarines with 20 launch tubes each and four warheads per missile, these boats carry about 960 warheads.
In storage
The U.S. maintains about 2,000 nuclear warheads in storage.
How it began
The atomic bomb was tested only once before being used in Japan — an event physicist J. Robert Oppenheimer said brought to mind words from Hindu scripture: “Now I am become death, destroyer of worlds.”
The concept was simple: driving together enough uranium or plutonium at high enough speeds will create a “critical mass” so quickly that it will start an uncontrolled, nearly instantaneous chain reaction of neutrons knocking apart atomic nuclei.
Only 1.09 kg of the 64 kg of uranium in Little Boy became energy.
World’s nuclear stockpile
80 years after the atomic flash set fire to Hiroshima, thousands of nuclear weapons sit in arsenals around the world, ready to deploy by aircraft or missile. The Arms Control Association estimates that there are nearly 14,000 such weapons, and that the United States and Russia account for the most by far: 6,185 for the United States and 6,490 for Russia, although of these only a third or so could be immediately used in a war.
Since 1945, more than 2,000 nuclear explosive tests have been carried out around the world.
The world’s two biggest nuclear powers, the United States and Russia, have not tested any nuclear weapons since 1992. Other countries trying to develop their own arsenals have carried out tests more recently.
The first series of thermonuclear tests took place on Nov. 1, 1952, on the small Pacific island of Elugelab at Enewetak Atoll in the Marshall Islands. The explosion yielded an energy equivalent of 10 megatons of TNT, an amount roughly 1,000 times as large as that released by the Hiroshima bomb.
The other states with nuclear weapons are Britain, China, France, India, Israel and Pakistan. South Africa developed nuclear weapons in the 1980s, but by the end of the decade decided to dismantle them. In 1994, the International Atomic Energy Agency confirmed all of the weapons had been destroyed.
As of September 2024, the U.S. stockpile of nuclear warheads consisted of 3,708 , down from 3,748 in 2023.
Sources: Nuclear Explosion Database, Bulletin of the Atomic Scientists, World Economic forum, UNESCO, Atomic Heritage Foundation, Union of Concerned Scientists, Britannica, Nuclear Explosion Database, armscontrolcenter.org