How many nuclear bombs were made in world war 2?

Answer 1

In August 1945 the US had three (3) atomic bomb weapons.

The test bomb nicknamed "the Gadget" ( a FAT MAN design type) was detonated at the TRINITY test site at Alamogordo Air Base , NM on 16 July 1945 (blast yield of 18.6 kilotons).

Two weapons, code named for the types of bombs designs and not the weapons themselves, were a LITTLE BOY (a MARK 1; bomb L-11) uranium U-235 bomb dropped on Hiroshima on 06 Aug 1945 (blast yield of 12-16 kilotons) called Operation: CENTERBOARD I and a FAT MAN (a MARK 3; bomb Y1561) plutonium Pu-239 bomb dropped on Nagasaki on 09 Aug 1945 (blast yield of 20 kilotons) called Operation: CENTERBOARD II. The third bomb also a FAT MAN (MARK 3) intended for Kokura on 19 Aug 1945 Operation: CENTERBOARD III was not used. Niigata and Yokohama were the next two (2) of the 17 (seventeen) targeted Japanese cities not bombed. Tokyo was considered a target city only of last resort since the Emperor, the Supreme War Council, the Prime Minister and Cabinet, and the Imperial Army and Navy General Staffs would have to survive to order an unconditional surrender.

The US had plans to manufacture and assemble one (1) more LITTLE BOY U-235 uranium bomb and up to twelve (12) additional FAT MAN Pu-239 plutonium bombs to drop on the targeted Japanese cities before the invasion of Japan code named Operation: DOWNFALL on 01 Nov 1945, but the surrender of Japan 14 Aug 45 (V-J Day) halted production and assembly of further atomic weapons until the Operation: CROSSROADS tests in June 1946.

Sources:

Pincher - D. A. Rosenberg 1989

Silverplate Bombers - R. H. Campbell 2005

The Decision to Use the Atomic Bomb - G. Alperovitz 1995

Making of the Atomic Bomb - R. Rhodes 1987

The General and the Bomb - W. Lawren 1988

Now It Can Be Told - L. Groves 1983