PCB + Vias Equivalent Thermal Conductivity

Governing Formula (Parallel Conduction): here f is volume fraction or area fraction of copper, k is thermal conductivity.

k_EQ = k_FR4 * (1 − f) + k_Cu * f. Actual PCB thermal conductivity may be lower due to: Via plating thickness (not solid copper), Air voids and Thermal contact resistance. For plated (hollow) vias, effective conductivity is typically 30 ~ 50% lower than with the solid-vias estimated below.

PCB Area [mm²] Number of Vias Via Diameter [mm] FR-4 Thermal Conductivity [W/m·K] Copper Thermal Conductivity [W/m·K] Calculate