Tons Of TNT to Kilojoules (tTNT to kJ)

1 ton of TNT equals 4,184,000 kilojoules exactly.

1 ton of TNT = 4,184,000 kilojoules

How to convert tons of TNT to kilojoules

To convert tons of TNT to kilojoules, multiply the number of tons of TNT by 4,184,000. This factor is exact. To go the other way, multiply kilojoules by 2.390057361×10⁻⁷ (rounded).

kilojoules = tons of TNT × 4,184,000

Example: 10 tons of TNT = 41,840,000 kilojoules.

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

About these units

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

Kilojoule (kJ)

Metric (SI)Current unit

1,000 joules. Food labels in many countries give energy in kilojoules.

Most food labels around the world express energy in kilojoules, which is the calorie's long retirement in action. The calorie came out of heat measurement, and the 1948 CGPM resolution stated that the joule should be preferred as the unit of heat. Labels that still show kilocalories alongside kilojoules rely on the thermochemical calorie of exactly 4.184 joules, so one kilocalorie is about 4.184 kJ.

The kilojoule is a convenient size for a body's daily bookkeeping. A person at rest uses about 5,000 kJ, or roughly 1,200 kcal, per day, and the recommended intake for a moderately active woman is given as 2,000 food calories, which is about 8,400 kJ.

Smaller physical comparisons land in the same range. One watt-hour is 3.6 kJ, a British thermal unit is about 1.1 kJ, exploding a gram of TNT releases about 4.2 kJ, and an alkaline AA battery holds about 9 kJ.

1 kilojoule = 1,000 joules (exactly).

Sources: Wikipedia: Kilojoule; Wikipedia: Joule; Wikipedia: Orders of magnitude (energy)

Related conversions

See all energy units.