The heat evolved when an aliquot of host solution is added to a solution containing the guest is the sum of contributions from each reaction
where  is a measured heat change value (corrected for all extraneous heat contributions) at data point j,  is the amount of heat absorbed or emitted when 1 mole of the ith reaction product is formed and  is the actual change in the number of moles of that product at that data point. is calculated by solving the equations of mass-balance with given values of the equilibrium constants. If the equilibrium constant values are known, the standard enthalpy change may be calculated by a linear least-squares process, otherwise a non-linear method of data-fitting must be used.
Isothermal titration calorimetry is commonly used to determine the values of both an equilibrium constant and the corresponding standard reaction enthalpy. The manufactures of ITC instruments supply some software with which these quantities may be obtained from experimental data values.