The thermal resistance is a physical quantity and the reciprocal of the thermal conductivity. For heat-critical projects you may possibly need the total thermal resistance of your metal core PCBs.
It is composed of the thickness-dependent individual resistances of:
You can select the thickness when calculating your metal core PCB in the PCB calculator.
Below you can calculate the total thermal resistance:
Calculator for thermal resistance
If you use the good Multi-CB standard specifications (35μm Cu, 100μm insulation with 2W / mK and 1.5mm aluminum thickness) the total thermal resistance is 0.6080 K/W.
I.e. per 1W power dissipation, a temperature difference of approx. 0.61 Kelvin (= 0.61 ° C) arises.