Coal grade is an economic or technological classification of the relative quality of a coal for a particular use. A variety of grades of coal are defined for different uses or markets in different industries and countries, and for the needs of a particular process or by regulations concerning the process or end-use product. The terms are process- or product-specific. For example, a coal which can be used to generate steam for electricity, may not be a high-grade coal for metallurgical uses. Terms such as low-ash or low-sulfur are also examples of grade terms. Different quality grades are used in different coal markets.
Coal can also be defined and classified based on: