What does API gravity measure?

What does API gravity measure?

• A. Test of the weight of a given volume of fuel vs the weight of an equal volume of water at 60°F
• B. The viscosity of fuel
• C. The boiling point of fuel
• D. The color of fuel

Answer: (A)

API gravity measures how dense a petroleum liquid is compared with water at a standard temperature (60°F). It’s essentially a density comparison: you weigh a fixed volume of the fuel and compare it to the weight of the same volume of water at 60°F. The result tells you whether the liquid is lighter or heavier than water—higher API gravity means lighter than water, lower means heavier. This standardized density value is useful for classifying crudes and fuels. It’s not about viscosity, boiling point, or color.

API gravity measures how dense a petroleum liquid is compared with water at a standard temperature (60°F). It’s essentially a density comparison: you weigh a fixed volume of the fuel and compare it to the weight of the same volume of water at 60°F. The result tells you whether the liquid is lighter or heavier than water—higher API gravity means lighter than water, lower means heavier. This standardized density value is useful for classifying crudes and fuels. It’s not about viscosity, boiling point, or color.