Enter the average atomic mass (g/mol) and the reference standard (g/mol) into the Atomic Ratio Calculator. The calculator will evaluate and display the Atomic Ratio. 

Atomic Ratio Formula

The following formula is used to calculate the Atomic Ratio. 

  • Where AR is the Atomic Ratio ( )
  • AAM is the average atomic mass (g/mol) 
  • RS is the reference standard (g/mol) 

To calculate the atomic ratio, divide the average atomic mass by the reference standard.

How to Calculate Atomic Ratio?

The following example problems outline how to calculate Atomic Ratio.

Example Problem #1:

  1. First, determine the average atomic mass (g/mol).
    • The average atomic mass (g/mol) is given as: 3.67.
  2. Next, determine the reference standard (g/mol).
    • The reference standard (g/mol) is provided as: 4.00.
  3. Finally, calculate the Atomic Ratio using the equation above: 


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

AR = 3.67 / 4.00 = .9175

Example Problem #2: 

For this problem, the variables required are provided below:

average atomic mass (g/mol) = 7.89

reference standard (g/mol) = 9.00

Test your knowledge using the equation and check your answer with the calculator above.

AR = AAM / RS = ?