Joules to Tons Of TNT (J to tTNT)

1 joule equals 2.390057361×10⁻¹⁰ tons of TNT (rounded).

1 joule = 2.390057361×10⁻¹⁰ tons of TNT

How to convert joules to tons of TNT

To convert joules to tons of TNT, multiply the number of joules by 2.390057361×10⁻¹⁰. The factor is rounded to 10 significant digits. To go the other way, multiply tons of TNT by 4,184,000,000.

tons of TNT = joules × 2.390057361×10⁻¹⁰

Example: 10 joules = 2.390057361×10⁻⁹ tons of TNT.

The 'calorie' on food labels is really a kilocalorie. The thermochemical calorie (4.184 J) is used here unless marked IT.

About these units

Joule (J)

Metric (SI)Current unit

The SI unit of energy: the work done by a force of one newton over one meter, or one watt for one second.

James Prescott Joule was born in Salford on 24 December 1818, the son of a wealthy brewer, and later ran the family brewery while treating science as a serious hobby. In June 1845 he told a British Association meeting in Cambridge about his best-known experiment: a falling weight turned a paddle wheel inside an insulated barrel of water, and the water warmed up. Mechanical work turned into heat at a fixed rate, which supported energy conservation and undermined the caloric theory of heat.

The unit came later. On 23 August 1882 Carl Wilhelm Siemens proposed at a British Association meeting that a unit of heat equal to 10 million ergs be named the joule, and in 1889 the second International Electrical Congress adopted it alongside the watt. Joule died that same year. In 1948 the CGPM added that the joule should be preferred to the calorie as the unit of heat, and it entered the SI in 1960.

For scale, one joule is about the energy needed to lift an apple of roughly 102 g by one meter. A 56 g tennis ball moving at 6 m/s carries about one joule of kinetic energy.

The joule is the reference unit for energy on this site.

Sources: Wikipedia: Joule; Wikipedia: James Prescott Joule

Ton Of TNT (tTNT)

ScientificCurrent unit

Exactly 4.184 gigajoules by convention (one tonne of TNT). The unit for explosions; a megaton is a million of them.

Explosive yields are quoted against a reference charge, and the ton of TNT is the one that stuck. Real TNT does not release a single fixed amount of energy: measured values run near 4,686 joules per gram, calculations give about 4,853, and a large open blast can burn more of its products in air than a small one. To sidestep the argument, the energy of a gram of TNT was set by convention at 4,184 joules, one kilocalorie, so a ton is exactly 4.184 gigajoules.

That makes a kiloton 4.184 terajoules and a megaton 4.184 petajoules. The scale is mostly used for nuclear weapons and asteroid impacts. The Hiroshima bomb is usually put at about 15 kilotons (63 terajoules) and the Nagasaki bomb at about 20 kilotons (84 terajoules). NIST lists the ton of TNT at 4.184 x 10^9 joules as an exact factor, matching the convention used here.

1 ton of TNT = 4,184,000,000 joules (exactly).

Sources: Wikipedia: TNT equivalent; NIST SP 811, Appendix B.8

Related conversions

See all energy units.