Thermal Resistance Calculator

About this calculator

Thermal resistance quantifies how strongly a material layer resists conductive heat flow: R = L / (k·A), where L is thickness, k is the material's thermal conductivity, and A is the cross-sectional area. It behaves exactly like electrical resistance in Ohm's law — heat flow Q equals the temperature difference divided by R (Q = ΔT/R), and layers in series simply add their resistances.

HVAC engineers and building scientists use thermal resistance to evaluate walls, roofs, and windows for energy efficiency (it's the physical basis behind R-values on insulation), while electronics engineers use the identical formula to size heat sinks and predict junction temperatures in semiconductor packages. Enter the thickness, conductivity, and area to find the thermal resistance.