API Gravity Calculator

What is API Gravity? (Meaning & Definition)

If you are asking what is api gravity, the official api gravity definition refers to a standard developed by the American Petroleum Institute. The api gravity meaning is essentially a gauge of how heavy or light a petroleum liquid is compared to water. It is an inverse measure: the higher the API gravity, the lighter the fluid.

Using an api gravity calculator like the one above is the fastest way for petroleum engineers, traders, and lab technicians to bridge the gap between field readings and laboratory formulations.

The API Gravity Formula

Understanding the mathematical relationship of api gravity density is critical for refinery operations. Converting specific gravity to api gravity, or moving from density to api gravity, relies on these standard baseline equations calibrated at 60°F (15.6°C):

Whether you need to convert api gravity to density (Kg/L) or vice versa, the api gravity formula proves that liquids with an API greater than 10 float on water, while those less than 10 will sink.

API Gravity of Water, Crude Oil, and Gasoline

Because the scale is based on water, the api gravity of water is exactly 10.0 at 60°F. However, petroleum products vary wildly:

• API Gravity of Gasoline: Refined products are incredibly light. The api gravity of gasoline typically ranges between 50 and 70 API.
• API Gravity of Crude Oil: The api gravity of crude oil directly dictates its market value. Light crude (31-45 API) is highly prized because it yields more gasoline and diesel, while heavy crude (< 20 API) yields asphalt and heavy fuel oils.

Global Benchmarks: Brent, WTI, and Merey Crude

In global oil trading, crude is priced against specific regional benchmarks with known API properties:

Traders closely watch Brent crude api gravity sulfur content. With an API around 38.3 and a low sulfur content of roughly 0.37%, Brent is a premium "light sweet" crude. West Texas Intermediate api gravity (WTI) is slightly lighter at 39.6. Conversely, the Venezuelan Merey crude api gravity (also searched as api gravity venezuelan merey crude) sits at a dense 16.0, making it a heavy crude that requires specialized, intensive refining.

Temperature Correction to 60°F

Because oil expands when heated, field hydrometer readings must be standardized. If you measure an oil at 80°F in the field, you must use an api gravity correction to 60°f calculator (often typed as api gravity correction to 60 f calculator) to find its true value. These calculators utilize complex ASTM D1250 petroleum measurement tables to shrink the volume mathematically back down to the 60°F international baseline.