Thermal Diffusivity Calculator
Thermal diffusivity measures how quickly temperature changes spread through a material relative to its heat storage. It depends on conductivity, density and specific heat.
How to use this calculator
- Enter positive conductivity, density and specific heat values using compatible SI units.
- Check that all inputs use the same units, period and population scope.
- Change one assumption at a time when comparing scenarios.
Formula used by thermal diffusivity calculator
α = k ÷ (ρcₚ).
- α = k ÷ (ρcₚ).
- The simple relation assumes uniform material properties and excludes phase changes, moisture effects and layered assemblies.
- The tool validates inputs and rounds displayed figures for readability; it does not validate assumptions against external records.
Worked examples
Worked example
For conductivity 0.8 W/(m·K), density 1,800 kg/m³ and specific heat 840 J/(kg·K), α is about 5.29 × 10⁻⁷ m²/s.
0.8 ÷ (1,800 × 840) m²/s.
The calculator returns diffusivity in m²/s and mm²/s.
Understanding the result
Thermal diffusivity measures how quickly temperature changes spread through a material relative to its heat storage. It depends on conductivity, density and specific heat.
The simple relation assumes uniform material properties and excludes phase changes, moisture effects and layered assemblies.
Important notes
The simple relation assumes uniform material properties and excludes phase changes, moisture effects and layered assemblies.
Treat the result as an estimate from the entered assumptions. For safety, legal, engineering, health or commercial decisions, verify relevant specifications and professional guidance.
Frequently asked questions
Is diffusivity the same as conductivity?
No. Conductivity describes heat-flow ability; diffusivity also accounts for density and heat capacity.
Does higher diffusivity mean heat flows faster?
It means temperature disturbances spread more quickly under the simplified model, but boundary conditions still matter.
How should I interpret this result?
The simple relation assumes uniform material properties and excludes phase changes, moisture effects and layered assemblies.
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This page provides a calculation tool plus explanatory information so you can understand what the result means and when the underlying method may not fit your situation.