Enter your Material Thickness, Thermal Conductivity (k), and Heat Transfer Area to calculate Thermal Resistance (R) — plus Thermal Resistance per Unit Area and Thermal Conductance. Pick a Common Material from the optional dropdown to skip the lookup and let the calculator fill in k for you.
Thermal Resistance (R)
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Thermal Resistance per Unit Area
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Thermal Conductance
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Thermal resistance is a measure of how much a material opposes the flow of heat through it. It's calculated as the temperature difference divided by the heat flow rate, expressed in units of K/W (Kelvin per Watt) or °C/W.
Thermal conductivity (k) measures how well a material conducts heat, while thermal resistance (R) measures how much it opposes heat flow. They are inversely related: R = L/(k×A), where L is thickness and A is area.
Thermal resistance is measured in K/W (Kelvin per Watt) or °C/W (degrees Celsius per Watt). For thermal resistance per unit area, the units are m²K/W or m²°C/W.
For thermal interface materials, use R = t/(k×A), where t is the thickness, k is the thermal conductivity, and A is the contact area. This calculator handles the conversion between different units automatically.
Thermal conductance is the reciprocal of thermal resistance (G = 1/R). It measures how easily heat flows through a material. Higher conductance means better heat transfer, while higher resistance means better insulation.
Area affects the total thermal resistance because heat flow is proportional to the cross-sectional area. A larger area provides more pathways for heat to flow, reducing the total thermal resistance.
Materials with low thermal conductivity have high thermal resistance. Examples include wood, foam insulation, air gaps, and ceramic materials. These are good insulators that resist heat flow.
The calculator automatically handles unit conversions. For manual conversion: 1 m²K/W = 5.678 hr⋅ft²⋅°F/Btu. Always ensure thickness and area units are consistent when calculating manually.