Heat Transfer Calculator

Heat Conduction

Heat flows through solids by conduction when a temperature difference exists across a material. Fourier's law for steady one-dimensional conduction gives the heat transfer rate through a plane wall or slab.

Conduction Formula

$$Q = \frac{kA\Delta T}{L}$$

$Q$ is heat transfer rate in watts, $k$ is thermal conductivity in W/(m·K), $A$ is cross-sectional area in m², $\Delta T$ is the temperature difference across the material in kelvin, and $L$ is thickness in meters.

Applications

Use this formula for building insulation, heat sinks, furnace walls, and any steady-state conduction through a uniform layer. Higher conductivity or area increases heat flow; thicker materials reduce it.

Frequently Asked Questions

What is thermal conductivity?

Thermal conductivity $k$ measures how easily a material conducts heat. Metals like copper have high $k$ (about 400 W/(m·K)); insulators like fiberglass have low $k$ (about 0.04 W/(m·K)).

When does steady-state conduction apply?

Steady state means temperature at each point is constant over time. The formula applies when heat in equals heat out and no energy is stored in the material.

How do I convert thickness from millimeters?

Divide millimeters by 1,000 to get meters. For example, 120 mm = 0.12 m. All inputs in this calculator use SI units.

What is heat flux?

Heat flux is heat transfer rate per unit area: $q = Q/A$ in W/m². It describes how intensely heat crosses a surface.

Does this include convection or radiation?

No. This calculator covers conduction only. Convection uses the heat transfer coefficient; radiation follows the Stefan-Boltzmann law.

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Heat Conduction

Conduction Formula

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Frequently Asked Questions

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