Enter the number of atoms per unit cell, the atomic weight, and the volume of a unit cell into the calculator to determine the theoretical density. This calculator can also evaluate any of the variables in the formula below when given the other variables.

Theoretical Density Formula

The formula for calculating the theoretical density is as follows: 

ρ = (n*A)/(V*N)
  • Where ρ is the density (g/cm^3)
  • n is the number of atoms per unit cell
  • A is the atomic weight (g/mol)
  • V is the volume per unit cell (cm^3/cell)
  • N is Avogadro’s number (6.023*10^23)

To calculate a theoretical density, multiply the number of atoms per unit cell by the atomic weight, then divide by the result of the product of the volume per unit cell multiplied by Avogadro’s number.

Theoretical Density Definition

A theoretical density is defined as the maximum density of a material or element that could be achieved assuming there are no voids or contaminants in the overall material.

What is the theoretical maximum density?

The theoretical maximum density of an element or material can be calculated using the formula p = (n*A)/(V*N). This represents the true or maximum density the material can reach in a given sample.

How to calculate a theoretical density?

  1. First, determine the number of atoms per cell of material or element.
  2. Next, determine the atomic weight. Calculate the average weight of all of the elements in the material.
  3. Next, determine the volume per unit cell. Typically this is 1 cm^3 per cell.
  4. Finally, calculate the theoretical density. Using the formula along with Avogadro’s number, you can calculate the theoretical density.