Here's some code demonstrating point and vector quantity conversions for Fahrenheit->Kelvin (unit_example_20.cpp). This code works correctly and is included in the most recent release of mcs::units in the Vault (mcs_units_v0.7.0_alpha_7)... The point<> and vector<> classes are toys for demo purposes only. quantity<fahrenheit::temperature,point<> > T1p(point<>(32) *fahrenheit::degrees); quantity<fahrenheit::temperature,vector<> > T1v(vector<>(32) *fahrenheit::degrees); quantity<SI::temperature,point<> > T2p(T1p); quantity<SI::temperature,vector<> > T2v(T1v); std::cout << T1p << std::endl << T2p << std::endl << T1v << std::endl << T2v << std::endl << std::endl; Outputting : { 32 } F { 273.16 } K [ 32 ] F [ 17.7778 ] K The main shenanigans happen in the specialization for conversion_helper to point and vector quantities of temperatures... Matthias ---------------------------------------------------------------- Matthias Schabel 2859 Glen Oaks Drive Salt Lake City, UT 84109 801-706-5760 (cell) 801-484-0811 (home) matthias at stanfordalumni dot org ----------------------------------------------------------------