Use of mass as proxy for energy

The tonne of trinitrotoluene (TNT) is acclimated as a proxy for energy, usually of explosions (TNT is a accepted top explosive). Prefixes are used: kiloton(ne), megaton(ne), gigaton(ne), abnormally for cogent nuclear weapon yield, based on a specific agitation activity of TNT of about 4.2 MJ/kg (or one thermochemical calorie per milligram). Hence, 1 kt TNT = 4.2 TJ, 1 Mt TNT = 4.2 PJ.

The SI assemblage of activity is the joule. Assuming that a TNT access releases 1,000 baby (thermochemical) calories per gram (4.2 kJ/g), one tonne of TNT is agnate to 4.2 gigajoules.