The Nuclear Testing Tally

Contacts: Daryl Kimball, Executive Director, (202) 463-8270 x107

Since the first nuclear test explosion on July 16, 1945, at least eight nations have detonated over 2,000 nuclear tests at dozens of test sites around the globe, including Lop Nor in China, the atolls of the Pacific, Nevada, and Algeria where France conducted its first nuclear device, Western Australia where the U.K. exploded nuclear weapons, the South Atlantic, Semipalatinsk in Kazakhstan, across Russia, and elsewhere.

Most of the test sites are in the lands of indigenous peoples and far from the capitals of the testing governments. A large number of the early tests—528—were detonated in the atmosphere, which spread radioactive materials through the atmosphere. 

The 1963 Limited Test Ban Treaty brought about the end of most, but not all, nuclear test explosions in the atmosphere. However, many underground nuclear blasts have also vented radioactive material into the atmosphere and left radioactive contamination in the soil.

Through nuclear test explosions, the nuclear testing nations have been able to proof-test new warhead designs and create increasingly sophisticated nuclear weapons. The overwhelming majority of the nuclear weapon test detonations were for "weapons development" and "weapons effects" purposes.

Following Russian test moratorium in 1991 and a U.S. nuclear testing moratorium in 1992, multilateral negotiations on a global Comprehensive Test Ban Treaty (CTBT) began in 1994 and were concluded in 1996. The treaty was opened for signature on September 24, 1996. 

The CTBT, prohibits "any nuclear weapon test explosion or any other nuclear explosion" and has established an international test monitoring and verification system. Although the CTBT has not yet entered into force due to the failure of 9 key states to ratify the treaty, the treaty has helped to establish a strong legal and political norm against nuclear explosive testing.

Summary of Nuclear Testing and Test Ban Status By State

United States: (1,030 total nuclear test explosions; 1.054 including joint U.S.-UK tests)         
First test: July 16, 1945         
Last test: Sept. 23, 1992         
Signed CTBT: Sept. 24, 1996

USSR/Russia: (715 total nuclear test explosions)         
First test: Aug. 29, 1949         
Last test: Oct. 24, 1990         
Deposited CTBT Ratification: June 30, 2000, but "de-ratified" the treaty in 2023.

United Kingdom: (45 total nuclear test explosions)         
First test: Oct. 3, 1952         
Last test: Nov. 26, 1991         
Signed CTBT: Sept. 24, 1996         
Deposited CTBT Ratification: Apr. 6, 1998

France: (210 total nuclear test explosions)         
First test: Feb. 13, 1960         
Last test: Jan. 27, 1996         
Signed CTBT: Sept. 24, 1996         
Deposited CTBT Ratification: Apr. 6, 1998

China: (45 total nuclear test explosions)         
First test: Oct. 16, 1964         
Last test: July 29, 1996         
Signed CTBT: Sept. 24, 1996

India: (3 total nuclear test explosions²)         
First test: May 18, 1974.         
Last test: May 13, 1998.         
Not a CTBT signatory.

Pakistan (2 total nuclear test explosions³)         
First test: May 28, 1998.         
Last test: May 30, 1998.         
Not a CTBT signatory.

North Korea: (6 total nuclear test explosion)         
First test: Oct. 9, 2006.         
Last test: Sept. 3, 2017.         
Not a CTBT signatory.

Nuclear Testing By Year 

Rows in green represent years in which a new country began nuclear testing.