Enter the molar mass (g/mol) and the number of hydroxyl groups into the Equivalent Mass Calculator. The calculator will evaluate and display the Equivalent Mass. 

Equivalent Mass Formula

The following formula is used to calculate the Equivalent Mass. 

Meq = MM / HG

  • Where Meq is the Equivalent Mass (g/mol/group)
  • MM is the molar mass (g/mol) 
  • HG is the number of hydroxyl groups 

How to Calculate Equivalent Mass?

The following example problems outline how to calculate Equivalent Mass.

Example Problem #1:

  1. First, determine the molar mass (g/mol). 
    • The molar mass (g/mol) is given as: 15.
  2. Next, determine the number of hydroxyl groups. 
    • The number of hydroxyl groups is provided as: 6.
  3. Finally, calculate the Equivalent Mass using the equation above: 

Meq = MM / HG

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

Meq = 15 / 6 = 2.5 (g/mol/group)

Example Problem #2: 

For this problem, the variables needed are provided below:

molar mass (g/mol) = 76

number of hydroxyl groups = 34

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

Meq = MM / HG = ?