TNT Equivalent Calculator
Calculate TNT equivalent weight for any explosive using the heat of detonation ratio. Select from C4, RDX, HMX, PETN and more with interactive comparison charts.
About This Calculator
The TNT Equivalent Calculator converts the explosive energy of any substance into its equivalent weight of TNT (trinitrotoluene) using the internationally recognized heat of detonation formula. This calculator is essential for engineers, safety professionals, military personnel, mining operators, and physics students who need to compare explosive yields or assess blast energy equivalence.
The calculation uses the formula Weq = Wexp × (Hexp / HTNT), where HTNT = 4.184 MJ/kg is the standard heat of detonation of TNT. The ratio Hexp / HTNT is called the TNT factor, which represents the relative energy density of the explosive compared to TNT. For example, C4 has a TNT factor of 1.127, meaning it releases 12.7% more energy per kilogram than TNT.
Our calculator includes a comprehensive database of 21 common explosives with pre-loaded heat of detonation values: TNT, C4, RDX, HMX, PETN, Comp B, Torpex, Tritonal, ANFO, ammonium nitrate, and more. You can also enter a custom heat of detonation for any other explosive material. The results show the TNT equivalent weight, TNT factor, and include comparative charts for visual analysis.
TNT equivalent is widely used in blast engineering, protective structure design, demolition planning, mining operations, and as a unit for describing large energy releases such as asteroid impacts, nuclear weapon yields, and volcanic eruptions. One kiloton of TNT equals 4.184 terajoules of energy.
The heat of detonation values in this calculator are sourced from the United Nations IATG 01.80 (Formulae for Ammunition Management) standard, ensuring accurate and authoritative reference data for all included explosives.
Frequently Asked Questions
What is TNT equivalent?
TNT equivalent is a standard convention for expressing the energy released in explosions. It compares the energy output of any explosive to the energy released by detonating the same mass of TNT (trinitrotoluene), which releases 4.184 MJ per kilogram.
How is TNT equivalent weight calculated?
The TNT equivalent weight is calculated using the formula: Weq = Wexp × (Hexp / HTNT), where Wexp is the weight of the explosive, Hexp is its heat of detonation in MJ/kg, and HTNT is 4.184 MJ/kg. The ratio Hexp/HTNT is called the TNT factor.
What is the TNT factor of C4?
C4 has a TNT factor of approximately 1.127. This means 1 kg of C4 releases 1.127 times the energy of 1 kg of TNT. So 6.5 kg of C4 is equivalent to about 7.325 kg of TNT.
How many MJ does 1 kg of TNT release?
One kilogram of TNT releases 4.184 megajoules (MJ) of energy upon detonation. This standard value was adopted internationally as the benchmark for comparing explosive yields.
What explosives have the highest TNT factor?
Torpex and Tetrytol 75/25 have the highest TNT factor at 1.200, meaning they produce 20% more energy per kilogram than TNT. PETN (1.173), RDX (1.152), and HMX (1.152) also have high TNT factors.
Is TNT equivalent used outside of explosives?
Yes, the TNT equivalent is also used as a unit of energy for describing very large energy releases such as asteroid impacts, volcanic eruptions, nuclear weapon yields, and industrial accidents, where the energy is measured in kilotons or megatons of TNT.
What is the TNT factor of ammonium nitrate?
Ammonium nitrate has a TNT factor of 0.420, meaning it releases only 42% of the energy of TNT per kilogram. Despite its lower energy density, large quantities of ammonium nitrate have been used in devastating industrial accidents.
Can I calculate TNT equivalent for custom explosives?
Yes, select Custom from the explosive dropdown and enter the heat of detonation for your explosive in MJ/kg. The calculator will use the same formula to determine the TNT factor and equivalent weight.