What is oil graded based on?

Oil is graded based on its viscosity and density, which are often measured using the American Petroleum Institute (API) gravity scale. The viscosity indicates how easily the oil flows at specific temperatures, while the API gravity provides a measure of the oil's density compared to water. Additionally, oil can be classified by its sulfur content, distinguishing between sweet (low sulfur) and sour (high sulfur) crude oils. These factors help determine the oil's quality, market value, and suitability for various refining processes.