I would like to calculate the

I would like to calculate the trace width to impedance

Problem
I am working on a four layer circuit board that will contain some RF traces and would like to know the layer stack-up and spacing that you use in order to calculate the trace width to impedance numbers 

SoluTIon
2-Layer PCB - 0.031" finished thickness
Layer 1 - Copper - 0.0014" thick (1 oz. copper weight)
Core material - 0.028" thick - Dielectric Constant of 4.7
Layer 2 - Copper - 0.0014" thick (1 oz. copper weight)

Layer 1 - Copper - 0.0014" thick (1 oz. copper weight)
Laminate (prepreg) - 0.007" thick - Dielectric Constant of 4.6
Layer 2 - Copper - 0.0014" thick (1 oz. copper weight)
Core material - 0.014" thick - Dielectric Constant of 4.7
Layer 3 - Copper - 0.0014" thick (1 oz. copper weight)
Laminate (prepreg) - 0.010" thick - Dielectric Constant of 4.6
Layer 4 - Copper - 0.0014" thick (1 oz. copper weight)
Core material - 0.014" thick - Dielectric Constant of 4.7
Layer 5 - Copper - 0.0014" thick (1 oz. copper weight)
Laminate (prepreg) - 0.007" thick - Dielectric Constant of 4.6
Layer 6 - Copper - 0.0014" thick (1 oz. copper weight)