Specific gravity

Also known as: SPG

Specific gravity is an index used to measure the density of a liquid. Specific gravity is calculated as the ratio of the density of a liquid to the density of water. So any liquid with a density greater than water has a specific gravity greater than 1. Liquids with a density lower than water, which includes most crude oil grades and petroleum products, will have a specific gravity between 0.0 and 1.0.

In the oil industry, specific gravity is a common quality specification for finished products. However, for crude oil grades, the API gravity index is more commonly used.

Calculation of specific gravity from API gravity:

Specific gravity = 141.5/(API gravity + 131.5)

McKinsey uses cookies to improve site functionality, provide you with a better browsing experience, and to enable our partners to advertise to you. Detailed information on the use of cookies on this Site, and how you can decline them, is provided in our cookie policy. By using this Site or clicking on "OK", you consent to the use of cookies.