Calculate explosion yield in MJ and TNT equivalent from an explosive’s mass, using the 4.184 MJ/kg TNT convention or your own energy density value.

Default 4.184 MJ/kg is the TNT-equivalent convention. Enter your material’s documented value if you have one.

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Explosion Yield Formula

The following formula is used to calculate the explosion yield.

Y = M × E

Variables:

  • Y is the explosion yield (megajoules)
  • M is the mass of the explosive material (kilograms)
  • E is the energy per unit mass (megajoules per kilogram)

To calculate the explosion yield, multiply the mass of the explosive material by the energy per unit mass.

What is Explosion Yield?

Explosion yield expresses released energy, commonly in joules or TNT-equivalent units. One tonne of TNT equivalent means 4.184 GJ by convention; it is a metric tonne of 1,000 kg, not a US short ton. Energy alone does not determine pressure, damage or safe separation. The mass calculation assumes the specified energy per unit mass applies to the entered material and conditions.

How to Calculate Explosion Yield?

The following steps outline how to calculate the Explosion Yield.

  1. First, determine the mass of the explosive material (M) in kilograms.
  2. Next, determine the energy per unit mass (E) in megajoules per kilogram.
  3. Next, gather the formula from above = Y = M * E.
  4. Finally, calculate the Explosion Yield (Y) in megajoules.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Mass of the explosive material (M) = 50 kilograms

Energy per unit mass (E) = 4.184 megajoules per kilogram (the conventional TNT energy basis). With 50 kg, Y = 50 × 4.184 = 209.2 MJ, or 50 kg TNT equivalent. This is a unit-equivalence example, not a measured material performance claim.