# Thermal Conductivity Conversion

I need to convert a thermal conduction unit W/m.K to Btu/ft.h.°F. I have 400 W/m.K and I need to find this value in Btu/ft.h.°F. I know that 1W=3.41214 Btu/h, 1m=3.2808ft and 1K=-457,87°F.I replaced all the values in the equation and got to -0.9085 Btu/ft.h.°F. But these values are incorrect according to internet queries and also in the book, could someone tell me what I'm missing?