A tool exists that provides a mechanism to convert between density, typically expressed as specific gravity or relative density, and a scale developed by the American Petroleum Institute (API) to measure the relative density of petroleum liquids. This conversion is essential for characterizing and classifying crude oil and related products. For example, a substance with a specific gravity of 0.85 will yield a corresponding value on the API gravity scale, indicating its relative lightness or heaviness compared to water.
The ability to accurately perform this conversion is important in the oil and gas industry for valuation, transportation, and refining processes. Knowing the API gravity of a crude oil shipment allows for standardized pricing and efficient allocation to appropriate refining units. Historically, this conversion provided a simple, hydrometer-based field method for quick assessment of petroleum liquid properties before sophisticated laboratory analyses became commonplace.