How To Calculate Void Volume

Understanding Void Volume and its Importance

When it comes to analyzing the properties of porous materials such as rocks, soils, or even biological tissues, one crucial parameter is the void volume. Void volume refers to the empty spaces or pores within a material, which can be filled with air, water, or other substances. Calculating the void volume is essential for various applications in fields such as geology, environmental science, and material science.

Why Calculate Void Volume?

The void volume of a material plays a significant role in determining its porosity, permeability, and storage capacity. Porosity is the fraction of a material’s volume that is occupied by voids, while permeability measures the ease with which fluids can flow through the material. Understanding these properties is crucial for predicting how a material will behave under different conditions, such as during oil and gas exploration, groundwater aquifer analysis, or designing filtration systems.

How To Calculate Void Volume

Methods for Calculating Void Volume

There are several methods for determining the void volume of a material, depending on the type of material and the available tools and equipment. Some common techniques include:

1. Water Saturation Method

This method involves saturating the material with water and measuring the increase in volume. By subtracting the initial volume of the dry material from the total volume after saturation, the void volume can be calculated.

2. Gas Displacement Method

In this method, a gas such as helium or nitrogen is used to displace the air in the voids of the material. By measuring the volume of gas required to fill the void spaces, the void volume can be determined.

See also  Wire Mesh Calculator

3. Mercury Intrusion Porosimetry

This advanced technique involves using mercury to fill the void spaces in the material at high pressure. By measuring the volume of mercury intruded into the material at different pressures, the pore size distribution and void volume can be calculated with great accuracy.

Calculating Void Volume from Porosity

One common approach to calculating void volume is by using the porosity of the material. The porosity of a material is typically expressed as a percentage and can be calculated using the formula:

Porosity (%) = (Void volume / Total volume) x 100

Once the porosity is known, the void volume can be determined by rearranging the formula:

Void volume = Porosity x Total volume / 100

By knowing the total volume of the material and its porosity, the void volume can be easily calculated using this simple formula.

Applications of Void Volume Calculations

Void volume calculations are essential in a wide range of applications, including:

  • Estimating oil and gas reserves in underground reservoirs
  • Designing drainage systems for agricultural and civil engineering projects
  • Investigating the effectiveness of water filtration systems
  • Characterizing the pore structure of materials for industrial manufacturing

By accurately determining the void volume of a material, scientists and engineers can make informed decisions and optimize their processes for maximum efficiency and effectiveness.


Calculating void volume is a crucial aspect of analyzing the properties of porous materials. By understanding the void volume, scientists and engineers can predict the behavior of materials under different conditions and optimize their use in various applications. Whether it’s in geology, environmental science, or material science, the accurate determination of void volume plays a vital role in advancing research and technology.