The New York Mercantile Exchange (NYMEX) defines light crude oil for domestic U.S. oil as having an API gravity between 37° API (840 kg/m3) and 42° API (816 kg/m3), while it defines light crude oil for non-U.S. oil as being between 32° API (865 kg/m3) and 42° API (816 kg/m3).

Light crude oil requires less processing and produces a greater percentage of gasoline and diesel than heavy oil. Light crude oil is primarily used to create fuels such as gasoline, diesel and aviation fuels.

Light crude is found through-out the world, but three benchmarks are commonly referenced and tend to set the standard in terms of price. They are West Texas Intermediate (API 39.6), Brent Crude (API 38.06), and Dubai Crude (API 31.0). Ghawar field in Saudi Arabia, the largest oil field in the world produces light crudes with API values that range from 33 degrees to 40 degrees. Note that an API of 31 is considered light by Arabian standards, but would not be light if produced inside of the United States.

Other types of light crude oil include the Mexican Almeca and Isthmus.

OLMECA is the “Lightest” of the Mexican crude oils (38 – 39 °API Gravity) and Sour (0.73% – 0.95% Sulfur content by weight). Its characteristics make it a good feedstock for lubricants and petrochemicals.

ISTHMUS ISTHMUS is a “Medium” (32 – 33 °API Gravity) and Sour (1.8% Sulfur content by weight) Crude Oil, with good gasoline and intermediate distillates (Diesel and Jet Fuel/Kerosene) yields. The highest economic value of this crude is obtained in refineries with FCC (Fluid Catalytic Cracker) units. Its quality is similar to Arab light crude and Russian Urals crude.