Enter the total substance mass (g) and the isotopes percent mass of the total mass (%) into the Isotope Mass Calculator. The calculator will evaluate and display the Isotope Mass. 

Isotope Mass Formula

The following formula is used to calculate the Isotope Mass. 

IM = TM * PM/100

  • Where IM is the Isotope Mass (g)
  • TM is the total substance mass (g) 
  • PM is the isotopes percent mass of the total mass (%) 

How to Calculate Isotope Mass?

The following example problems outline how to calculate Isotope Mass.

Example Problem #1:

  1. First, determine the total substance mass (g). 
    • The total substance mass (g) is given as: 89.
  2. Next, determine the isotopes percent mass of the total mass (%). 
    • The isotopes percent mass of the total mass (%) is provided as: 30.
  3. Finally, calculate the Isotope Mass using the equation above: 

IM = TM * PM/100

The values given above are inserted into the equation below and the solution is calculated:

IM = 89 * 30/100 = 26.7 (g)


Example Problem #2: 

For this problem, the variables needed are provided below:

total substance mass (g) = 90

isotopes percent mass of the total mass (%) = 24

This example problem is a test of your knowledge on the subject. Use the calculator above to check your answer. 

IM = TM * PM/100 = ?