Heat Conduction Calculator
Estimate steady heat flow through a uniform flat material layer.
Apply Fourier conduction through a flat layer
Steady heat conduction through a uniform flat layer follows Fourier's law: thermal conductivity times area times temperature difference divided by thickness. This calculator reports heat-transfer rate in watts when SI units are used, plus heat flux per square meter. It supports quick insulation comparisons, wall-section checks, and classroom problems where surface temperatures and material conductivity are already known.
With conductivity 0.8 watts per meter-kelvin, area 10 square meters, temperature difference 20 kelvin, and thickness 0.2 meter, the predicted heat rate is 800 watts. Heat flux is 80 watts per square meter. Doubling thickness halves the rate, while doubling area or conductivity doubles it under unchanged boundary conditions.
Keep geometry and boundary assumptions visible
The model is one-dimensional and steady, with constant conductivity, uniform surface temperatures, and no contact resistance. It excludes convection films, radiation, thermal bridges, moisture, heat storage, and layered construction unless those effects are separately converted into resistance. Values are computed in your browser. Building and equipment decisions should use assemblies, codes, and measured material data rather than a single ideal layer.
Frequently Asked Questions
What units produce watts?
Use conductivity in watts per meter-kelvin, area in square meters, temperature difference in kelvin, and thickness in meters.
Can this calculate a multilayer wall?
Not directly. Combine layer thermal resistances and surface-film resistances for a complete assembly.
Does temperature difference need Celsius or kelvin?
Either scale works for a temperature difference because their degree increments are equal.
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