Heat Conduction Rate

Also known as fourier's law · conduction through a wall

P = \tfrac{k A \Delta T}{d}

P =

k =

A =

ΔT =

d =

Enter your known values, leave one input blank, and solves for the missing one. Try different units for next level excitement!

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Fourier's law for steady-state conduction: heat flow grows with conductivity, area, and temperature difference, and shrinks with thickness. A single glass pane (k = 0.96 W/(m·K), 1.5 m², 3 mm thick) with 20 K across it would pass a startling 9.6 kW through the glass itself — which is why real windows rely on trapped air gaps, since air's k is only about 0.026.

Heat Conduction Rate

P = \tfrac{k A \Delta T}{d}

Where

$P$ = Heat flow rate
$k$ = Thermal conductivity
$A$ = Cross-sectional area
$\Delta T$ = Temperature difference
$d$ = Thickness

Missing one of these? Work it out first, then come back

Heat flow rate — Heat Flow from Thermal Resistance, Conduction Through a Pipe Wall
Thermal conductivity — Thermal Resistance of a Plane Wall, Conduction Through a Pipe Wall
Cross-sectional area — Volumetric Flow Rate (Q = Av), Resistance of a Wire (R = ρL/A)
Temperature difference — Heat Flow from Thermal Resistance, Heat Flux Through Insulation (q = ΔT/R)
Thickness — Thin-Film Constructive Interference (Bright Reflection), Thin-Film Destructive Interference (Dark Reflection)