Centistoke

Centistoke is a unit of kinematic viscosity. Kinematic viscosity is a measure of a fluid's resistance to flow under the influence of gravity. It is defined as the ratio of dynamic viscosity to density. The centistoke (cSt) is a sub-multiple of the stoke (St), which is the CGS (centimeter-gram-second) unit for kinematic viscosity. One stoke is equal to one square centimeter per second. Therefore, one centistoke is equal to one hundredth of a stoke, or 10⁻⁶ square meters per second (m²/s).

The centistoke is commonly used in the petroleum industry and for specifying the viscosity of oils and lubricants. For example, engine oils are often rated by their viscosity in centistokes at specific temperatures. A lower centistoke value indicates a thinner fluid that flows more easily, while a higher centistoke value indicates a thicker fluid with greater resistance to flow. The centistoke unit is convenient because many common fluids have viscosities that fall within a practical range when expressed in centistokes. For instance, water at room temperature has a kinematic viscosity of approximately 1 centistoke.