Since the Trinity test in the New Mexico desert in July 1945, eight countries have set off 2,055 nuclear test explosions. I mapped every one of them: where it was, who fired it, how big it was, and whose land or sea it was on.
The SIPRI list of nuclear explosions, compiled by Nils-Olov Bergkvist and Ragnhild Ferm for the Stockholm International Peace Research Institute and the Swedish Defence Research Establishment, records 2,051 explosions from 1945 to 1998 with a date, a position, a method of firing and an estimate of the yield. I added North Korea's six tests from 2006 to 2017. Two of the explosions in the list were not tests: the bombs dropped on Hiroshima and Nagasaki in August 1945. They are shown on the map for reference, but every number on this page counts tests only.
Most tests were small, and most were underground. A few dozen enormous atmospheric explosions in the 1950s and early 1960s, nearly all of them on remote islands, account for most of the energy ever released. This page tries to show both.
Each circle is one test, coloured by the country that fired it. The circle's radius grows with the cube root of the yield, the way the radius of blast damage does, so a 1,000 kiloton test is drawn ten times as wide as a 1 kiloton one. Press play to watch the years go by, drag the slider, or pick only atmospheric or underground tests. Click a circle for the record, or a site name for its story.
Circles: 2,055 tests, 1945 to 1998 from the SIPRI list (Bergkvist and Ferm 2000) and 2006 to 2017 from Wikipedia's list of North Korean tests. Yield is the middle of the lower and upper estimates; where the source gives "less than 20 kilotons" the circle is drawn at 10. Where many tests share one position in the source (hundreds at the Nevada Test Site share the same rounded coordinates), the circles are spread over a small disc up to 0.25 degrees across so each can be clicked; popups give the position as recorded. 24 records with no position are placed approximately and say so. Outlines: Natural Earth. Base map tiles © Esri.
The first years were slow: 1,030 tests would eventually be American, but there were only a handful before 1951. Then the Soviet Union, from 1949, and Britain, from 1952, joined in, and the numbers climbed. In 1958 there were 116 tests. Then the United States, the Soviet Union and Britain paused: there were 0 tests in 1959 and 3 in 1960, all of them French. When the Soviet Union broke the pause in September 1961 the result was the busiest two years of testing there has ever been. In 1962 there were 178 tests, 96 American and 79 Soviet: one every 2.1 days. 117 of them were in the open air.
Nuclear tests per year, 1945 to 2017
Stacked by country, or by where the device went off, or as explosive yield (megatons, central estimate). The shaded band is the 1958 to 1961 testing pause; dashed lines mark the treaties. Hover a bar.
The yield tells an even sharper story. The tests of 1961 and 1962 alone released 50% of all the explosive energy of every test ever made, most of it in a few dozen Soviet hydrogen bombs over Novaya Zemlya.
On 5 August 1963 the United States, the Soviet Union and Britain signed the Partial Test Ban Treaty, which banned tests in the atmosphere, in outer space and under water. Testing did not stop. It went underground. Before the treaty, 79% of tests were in the atmosphere or underwater; after it, 95% were underground. The number of tests hardly fell: about 49 a year from 1963 to 1992.
Two countries did not sign. France carried on testing in the atmosphere until 1974 (46 tests after the treaty, all in French Polynesia), and China until 1980 (23, at Lop Nur). The last atmospheric test anywhere was Chinese, on 16 October 1980.
Before and after the Partial Test Ban Treaty
Each country's tests before and after 5 August 1963, split by where the device went off. Hover a bar.
Yields are uncertain, and the SIPRI list gives most of them as a range. Taking the middle of each range, the 2,055 tests released about 546 megatons, somewhere between 429 and 664: the equivalent of 546 million tonnes of TNT. The Soviet Union and the United States account for 92% of it. The typical test was much smaller: the median was 10 kilotons, and 65% of tests had an upper estimate of 20 kilotons or less. The 85 tests of a megaton or more made up 80% of all the yield.
One place stands out. Novaya Zemlya, the Arctic islands where the Soviet Union fired its biggest bombs, took 51% of all the yield ever tested, in 130 tests. Nevada had 935 tests, 45% of the world's total, but most were small and underground.
Total explosive yield, by country or by test site
Central estimate in megatons; the thin line runs from the sum of the lower to the sum of the upper estimates. Hover a bar.
The largest explosion ever set off was the Soviet test known as Tsar Bomba, dropped by parachute over Novaya Zemlya on 30 October 1961. Its yield was about 50 megatons, 3,333 times the Hiroshima bomb and 9% of the yield of all tests put together. Of the twenty largest tests, 11 were Soviet and 9 American, and 12 took place in 1961 or 1962.
The largest American test was Castle Bravo, at Bikini Atoll on 1 March 1954 (28 February in the SIPRI list, which uses Greenwich time). Its yield, 15 megatons, was far larger than its designers expected. As the Wikipedia list of tests puts it, the unanticipated yield and a change in the weather spread fallout eastward onto the inhabited Rongelap and Rongerik atolls, which were soon evacuated; the crew of a Japanese fishing boat, the Daigo Fukuryū Maru, also fell ill, and one of them died.
The twenty largest nuclear tests
Central estimate of yield in megatons, with the source's range where it gives one. Hover a bar.
Most tests were on the testing country's own national territory: 82% of them, mostly underground in Nevada, Kazakhstan and Xinjiang. But the biggest atmospheric tests were usually set off far from the capitals that ordered them. 357 tests (17%) were in colonies, overseas territories, trust territories or another country's land, and they released 32% of all the yield. And 440 tests (21%) were on islands, which took 84% of the yield.
Whose land the tests were on
Share of tests and share of explosive yield, by the status of the land at the time of the test, and on islands against the mainland. Hover a bar.
Every one of France's 210 tests was outside metropolitan France: 17 in the Algerian Sahara, 11 of them after Algeria's independence in July 1962, and 193 on the atolls of Moruroa and Fangataufa in French Polynesia. Every one of Britain's 45 was abroad too: 12 in Australia, 9 on islands in the central Pacific that are now part of Kiribati, and 24 in Nevada. The United States held 66 tests at Bikini and Enewetak in the Marshall Islands, then a United Nations trust territory under American administration; together they released 54% of all American test yield. The Soviet Union and China tested only inside their own borders, though Semipalatinsk lay in the Kazakh Soviet republic, now independent Kazakhstan, and Lop Nur in Xinjiang.
The main test sites
Click a card to see the site on the map. Notes are kept short and sourced; see Sources below.
Most of the energy of nuclear testing was released over a few remote islands and atolls, far from the countries that ordered it.
The Comprehensive Nuclear-Test-Ban Treaty, which bans all nuclear explosions, opened for signature on 24 September 1996. It has not entered into force. The last American test was in 1992, the last Soviet one in 1990, the last British one in 1991; France stopped in January 1996 and China in July 1996. Since the treaty opened there have been 10 tests: 2 by India and 2 by Pakistan in May 1998, and 6 by North Korea between 2006 and 2017. In Wikipedia's words, there were no declared tests between Pakistan's Chagai-II and North Korea's first test, and none outside North Korea since.
North Korea's six tests
Estimated yield in kilotons, lowest to highest estimate as given on Wikipedia's list of North Korean tests, with the middle marked. For scale: the Hiroshima bomb, 15 kilotons. Hover a bar.
The six North Korean tests grew from 0.7 to 2 kilotons in 2006, possibly a fizzle, to 70 to 280 kilotons in September 2017, which North Korea claimed was a hydrogen bomb. All were underground, under the mountains at Punggye-ri. Large as that last test was, it was a small fraction of the biggest tests of the 1950s and 1960s. As of 2026, it has been 9 years since the last known nuclear test.
The tests. The main source is the list of nuclear explosions from 1945 to 1998 compiled by Bergkvist and Ferm (2000) for SIPRI and the Swedish Defence Research Establishment (FOA), as published by data is plural and the R for Data Science TidyTuesday project (2019). It gives each explosion's date, the testing country, a site code, a position, seismic magnitudes, depth or height, a lower and upper yield estimate, the purpose, a name where one is known and the method of firing. I added North Korea's six tests of 2006 to 2017 from Wikipedia's list of North Korean tests, taking the dates, positions and yield ranges from the page text only. Names for some of the largest Soviet and Chinese tests, and for the Indian and Pakistani tests, come from Wikipedia too.
Counting. This page counts 2,055 tests: 2,049 from the SIPRI list (its 2,051 explosions less Hiroshima and Nagasaki) and 6 North Korean. Other counts differ. Wikipedia's list gives 2,121, because it counts some salvo explosions, British safety trials and Soviet tests differently. Five devices fired together count as one test here, as they do in the SIPRI list.
Yields are estimates, many of them only an upper bound: 776 tests are recorded as "0 to" some figure. I use the middle of each range, and give the sum of the lower and upper estimates beside every total. Totals are dominated by a few dozen megaton tests, whose yields are well known, so the main findings do not depend on how the small tests are counted. Atmospheric here means in the air, on the ground, on a tower, barge or ship, on the water surface or in space; underground includes shafts, tunnels and shallow cratering shots; underwater is shown separately. Land status is the status of the place at the time of the test, as described in the sources below.
What this does not show. A map of tests is not a map of harm. Fallout drifted far from the sites; people living near Semipalatinsk, in the Marshall Islands, in Nevada's downwind communities, around Maralinga and in French Polynesia were exposed, as were many thousands of service personnel. The doses and their effects are studied elsewhere, notably by UNSCEAR, and are not in this data.