Enter the total number of atoms of the molecule (atoms) and the mass per molecule (AMU) into the Exact Mass Calculator. The calculator will evaluate and display the Exact Mass.

## Exact Mass Formula

The following formula is used to calculate the Exact Mass.

**EM = #A * MM**

- Where EM is the Exact Mass (AMU)
- #A is the total number of atoms of the molecule (atoms)
- MM is the mass per molecule (AMU)

## How to Calculate Exact Mass?

The following example problems outline how to calculate Exact Mass.

Example Problem #1:

- First, determine the total number of atoms of the molecule (atoms).
- The total number of atoms of the molecule (atoms) is given as: 3.

- Next, determine the mass per molecule (AMU).
- The mass per molecule (AMU) is provided as: 12.

- Finally, calculate the Exact Mass using the equation above:

EM = #A * MM

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

EM = 3 * 12 = 36 (AMU)

Example Problem #2:** **

For this problem, the variables needed are provided below:

total number of atoms of the molecule (atoms) = 8

mass per molecule (AMU) = 6

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

EM = #A * MM** = ?**