Disclaimer: Not to be confused with Compressibility factor .

A measure of resistance of a Continuum body to compression.

A measure of isothermal relative change in density or molar volume under a unit pressure variation:

c = \frac{1}{\rho} \left( \frac{\partial \rho}{\partial p} \right)_T = - \frac{1}{V_m} \left( \frac{\partial V_m}{\partial p} \right)_T

Symbol	Dimension	SI units	Oil metric units	Oil field units
	M^-1 L¹T²	Pa^-1	kPa^-1	psi^-1

Compressibility depends on the thermodynamic conditions at which it is measured and as such is not a material property.

c(p) = \frac{1}{p} - \frac{1}{Z} \frac{dZ}{dp}

c(p) =  - \frac{1}{B} \frac{dB}{dp}

c_T = \frac{1}{\rho} \left( \frac{\partial \rho}{\partial p} \right)_T

c_S = \frac{1}{\rho} \left( \frac{\partial \rho}{\partial p} \right)_S

See also