Calculate rock density, mass, or volume by selecting the value to solve and entering the required inputs in common units. Specific gravity assumes reference water at 1,000 kg/m³; porosity uses dry bulk and grain densities.

Use measured sample properties when available. Porosity calculations require dry bulk density and negligible mass of air in the pores.

Rock Density Formula

The following formula is used to calculate the Rock Density. 

RD = RM / RV
  • Where RD is the Rock Density (lbs/ft^3)
  • RM is the rock mass (lbs) 
  • RV is the rock volume (ft^3) 

To calculate the rock density, divide the rock mass by the rock volume.

How to Calculate Rock Density?

The following example problems outline how to calculate Rock Density.

Example Problem #1:

  1. First, determine the rock mass (lbs).
    1. The rock mass (lbs) is given as 90.
  2. Next, determine the rock volume (ft^3).
    1. The rock volume (ft^3) is provided as 3.
  3. Finally, calculate the Rock Density using the equation above: 

RD = RM / RV

The values given above are inserted into the equation below:

RD = 90 / 3 = 30 (lbs/ft^3)

Example Problem #2: 

For this problem, the variables needed are provided below:

rock mass (lbs) = 145

rock volume (ft^3) = 34

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

RD = RM / RV = 145 / 34 ≈ 4.264706 lbs/ft³