BTUs And Calories

WARNING: This page does not describe the selected car, but rather 41 other vehicles, including the 2003 BMW M5, 2003 BMW M3, 2003 BMW 540i, 2003 BMW 530i, and 2003 BMW 525i. However, it is still accessible from the selected car via links, so may be relevant.

Heat is measured in British Thermal Units (BTUs) and calories.

BTU - amount of heat energy required to raise one pound of water one degree Fahrenheit.
Calorie - amount of heat energy required to raise one gram of water one degree Celsius.

Fig 1: Identifying BTUs And Calories
Courtesy of BMW OF NORTH AMERICA, INC.