Physics

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Thermal Diffusivity Calculator.

Calculate thermal diffusivity from conductivity, density, and heat capacity.

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Thermal diffusivity: 0 m²/s

Thermal diffusivity

0.000000m²/s

Results update automatically as you type.

Use Cases

Material selection for heat dissipation

Engineers compare thermal diffusivity of materials to choose those that respond quickly to temperature changes, such as heat sinks or cooling fins.

Example: Compare aluminum (high diffusivity) vs. stainless steel for a heat sink design.

Transient heat transfer analysis

In simulations of heating or cooling processes, thermal diffusivity is a key input to predict temperature distribution over time.

Example: Estimate how fast a steel plate reaches uniform temperature after quenching.

Frequently Asked Questions

What is thermal diffusivity and why is it important?
Thermal diffusivity measures how quickly heat spreads through a material relative to its heat storage capacity. It's crucial in transient heat transfer problems, like cooling or heating processes, because it indicates the rate of temperature change within a material.
How is thermal diffusivity calculated?
Thermal diffusivity (α) is calculated by dividing thermal conductivity (k) by the product of density (ρ) and specific heat (cp): α = k / (ρ * cp). The result is in square meters per second (m²/s).
What units are used in this calculator?
This calculator uses thermal conductivity in W/(m·K), density in kg/m³, and specific heat in J/(kg·K). The resulting thermal diffusivity is in m²/s.

Tips & Common Mistakes

Tips

  • Ensure all input values are in the correct units: W/(m·K) for conductivity, kg/m³ for density, and J/(kg·K) for specific heat.
  • Double-check your density and specific heat values from reliable material property tables, as they can vary with temperature.
  • For anisotropic materials, use the appropriate directional thermal conductivity value.
  • Remember that thermal diffusivity is temperature-dependent; use values relevant to your operating temperature.

Common Mistakes to Avoid

  • Using thermal conductivity in different units (e.g., W/(cm·K)) without converting to W/(m·K).
  • Confusing specific heat capacity (J/(kg·K)) with heat capacity (J/K) – the latter is not per unit mass.
  • Forgetting that density must be in kg/m³, not g/cm³, leading to incorrect results.

Last updated: August 13, 2026