The CO2TablesSci Excel Add-In library calculates 34 thermodynamic and transport properties of carbon dioxide and also provides access to 8 constant properties used by the calculation engine. It allows 11 different combinations of input variables to be used in calculations. Input variables that can be used are: pressure, temperature, enthalpy, entropy, volume, internal energy and quality (vapor mass fraction). The library is fully integrated with Excel and it's functions can be used in the same way as any other Excel function.