In polymer science, inherent viscosity is the ratio of the natural logarithm of the relative viscosity of a polymer to its mass concentration.
Inherent viscosity is defined as 
where c is the mass concentration of the polymer (g/dL) and is the relative viscosity, which is defined as
where is the viscosity of the solution and is the viscosity of the solvent.
The unit of inherent viscosity is dL/g.