TNT Calculator

IME TNT Equivalence Calculator

The term "TNT equivalence" is a normalization technique for equating properties of an explosive to TNT, the standard. There are many ways to calculate "TNT equivalence" and the term is often misused because the property in question and basis for the equivalence are not defined.

This worksheet is primarily designed to assist mining companies in determining if they should submit form 9-4040-A to the U.S. Geological Survey. This form is part of the U.S. implementation of the Comprehensive Test Ban Treaty and is submitted voluntarily by mines that conduct blasts with over 300 short tons "TNT equivalent" of explosives.

This worksheet uses the property of energy called the heat of combustion or heat of explosion and is expressed in units of kilocalories per gram. This is one of the more common types of "TNT equivalence" and is the one used on USGS form 9-4040A.

Enter the weight of the explosive in either pounds or kilograms:
(For the purposes of USGS form 9-4040-A, enter the largest blast you did/will conduct in the last/next calander year.)
Enter the heat of combustion or the heat of explosion of the explosive:
(Use 0.88 kilocalories per gram for ANFO (ISEE Blasters' Handbook, 17th ed.)
-  kilocalories/gram
The equivalent amount of TNT is:
  in pounds
  in kilograms
    in short tons

If the number of Short Tons is larger than 300, you should submit USGS form 9-4040-A.

Although submission of USGS form 9-4040-A is not mandatory, IME recommends that applicable mining operations submit the form to keep U.S. antiproliferation authorities informed.