Enter the sum of the reactants (amu) and the product of the masses (amu) into the Calculator. The calculator will evaluate the Nuclear Q Value. 

Nuclear Q Value Formula

Q = (mr - mp) * .9315


  • Q is the Nuclear Q Value (GeV)
  • mr is the sum of the reactants (amu)
  • mp is the product of the masses (amu)

To calculate Nuclear Q Value, subtract the product of the masses from the sum of the reactants, then multiply by .9315.

How to Calculate Nuclear Q Value?

The following steps outline how to calculate the Nuclear Q Value.

  1. First, determine the sum of the reactants (amu). 
  2. Next, determine the product of the masses (amu). 
  3. Next, gather the formula from above = Q = (mr – mp) * .9315.
  4. Finally, calculate the Nuclear Q Value.
  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.

sum of the reactants (amu) = 2.748

product of the masses (amu) = 1.24

FAQ Section

What is AMU in nuclear physics?

AMU stands for Atomic Mass Unit. It is a standard unit of mass that quantifies mass on an atomic or molecular scale. In nuclear physics, it is used to express the masses of atomic particles and molecules.

Why is the Nuclear Q Value important?

The Nuclear Q Value is important because it represents the amount of energy released or absorbed during a nuclear reaction. It is a critical factor in assessing the feasibility and yield of nuclear reactions, including both fission and fusion processes.

How does the Nuclear Q Value affect nuclear reactions?

A positive Nuclear Q Value indicates that a nuclear reaction releases energy, making it exothermic. This is essential for energy-producing reactions, such as in nuclear power plants or stars. A negative Q Value suggests the reaction absorbs energy, which is significant in nuclear transmutation and certain types of experimental nuclear physics research.

Can the Nuclear Q Value be negative?

Yes, the Nuclear Q Value can be negative in cases where the nuclear reaction requires energy input to occur. This means that the mass of the products is greater than the mass of the reactants, resulting in an endothermic reaction where energy is absorbed rather than released.