Thermal Diffusivity Calculator

Understanding Thermal Diffusivity

Thermal diffusivity ($\alpha$) describes how quickly temperature changes propagate through a material. It combines three fundamental material properties into a single parameter: thermal conductivity ($k$), density ($\rho$), and specific heat capacity ($c_p$). The defining equation is $\alpha = k / (\rho \cdot c_p)$.

High-diffusivity materials like copper ($\alpha \approx 1.16 \times 10^{-4}$ m²/s) equalize temperature quickly, while low-diffusivity materials like rubber ($\alpha \approx 1 \times 10^{-7}$ m²/s) respond slowly. This property governs transient heat conduction problems and determines how long it takes for a body to reach thermal equilibrium.

Thermal Diffusivity Formula

The calculator uses the thermal diffusivity equation and its rearrangements:

• Thermal Diffusivity: $$\alpha = \frac{k}{\rho \cdot c_p}$$
• Thermal Conductivity: $$k = \alpha \cdot \rho \cdot c_p$$
• Density: $$\rho = \frac{k}{\alpha \cdot c_p}$$
• Specific Heat Capacity: $$c_p = \frac{k}{\rho \cdot \alpha}$$

Where $\alpha$ is thermal diffusivity (m²/s), $k$ is thermal conductivity (W/(m·K)), $\rho$ is density (kg/m³), and $c_p$ is specific heat capacity (J/(kg·K)).

How to Use the Calculator

1. Select the variable you want to solve for from the dropdown menu (Diffusivity, Conductivity, Density, or Specific Heat).
2. Enter the known values in the corresponding input fields.
3. The tool instantly calculates the result and displays all material properties.
4. Use the Details text area to view all values and copy the output.