 Because of the 100-degree interval, it was called a centigrade scale.Since the standardization of the kelvin in the International System of Units, it has subsequently been redefined in terms of the equivalent fixing points on the Kelvin scale, and so that a temperature increment of one degree Celsius is the same as an increment of one kelvin, though they differ by an additive offset of approximately 273.15.The United States commonly uses the Fahrenheit scale, on which water freezes at and boils at at sea-level atmospheric pressure.