TNT equivalent is a method of quantifying the energy released in explosions. The ton (or tonne) of TNT is a unit of energy equal to 4.184 gigajoules, which is approximately the amount of energy released in the detonation of one ton of TNT. The megaton is a unit of energy equal to 4.184 petajoules.
The kiloton and megaton of TNT have traditionally been used to rate the energy output, and hence destructive power, of nuclear weapons.
- The Little Boy atomic bomb dropped on Hiroshima on August 6, 1945, exploded with an energy of about 15 kilotons of TNT (63 TJ).
- During the Cold War, the United States developed hydrogen bombs with a maximum theoretical yield of 25 megatons of TNT (100 PJ); the Soviet Union developed a prototype weapon, nicknamed the Tsar Bomba, which was tested at 50 Mt (210 PJ).
- 1 megaton of TNT (4.2 PJ), when converted to kilowatt-hours, produces enough energy to power the average American household (in the year 2007) for 103,474 years. For example, the 30 Mt (130 PJ) estimated upper limit blast power of the Tunguska event could power the aforementioned home for just over 3,104,226 years. To put that in perspective: the blast energy could power the entire United States for 3.27 days
- The approximate energy released when the largest fragment of Comet Shoemaker-Levy 9 impacted Jupiter was estimated to be equal to 6 million megatons (or 6 trillion tons) of TNT. 
- A solar flare has the power of 2.5 X 10^25 megatons of TNT.