Important notes:

The width of the track is calculated in this way:

The first thing we do is calculate the section that the track will have to work at a given current and with a given increase of temperature:

Area[mils^2] = (Current[Amps]/(k*(Temp_Rise[deg. C])^b))^(1/c)

The width of the track is then calculate:

Width[mils] = Area[mils^2]/(Thickness[oz]*1.378[mils/oz])

Respecting the standard IPC-2221 for the inner layers the following parameter K for the dissipation: k = 0.024 will be assumed: k = 0.024

While for the outer layers parameter is: k = 0.048