Physics

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Thermal Expansion Calculator.

Calculate linear expansion of an unconstrained homogeneous bar.

On-device calculationNo signup
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Set your values

Results update as you type.

Length change: 0.0006 m

Length change

0.000600m
Final length: 1.0006 m

Final length

1.000600m

Results update automatically as you type.

Use Cases

Engineering design for temperature variations

Engineers can estimate how much a metal rod or beam will expand or contract with temperature changes, helping to design expansion joints or tolerances.

Example: A 10 m steel bridge span with α = 12e-6 1/K and ΔT = 30 K expands by 3.6 mm.

Physics education and lab work

Students and educators can quickly compute linear expansion for experiments or to verify theoretical predictions.

Example: Calculate the expansion of a 0.5 m aluminum rod heated by 50 K.

Frequently Asked Questions

What does the thermal expansion calculator do?
It calculates the change in length (linear expansion) of a solid bar when its temperature changes. You input the initial length, the material's expansion coefficient, and the temperature change, and it computes the resulting length change.
What units should I use for the inputs?
The calculator expects initial length in meters (m), expansion coefficient in per Kelvin (1/K), and temperature change in Kelvin (K). Ensure all inputs are in these units for accurate results.
Is this calculator suitable for all materials?
It is designed for homogeneous, unconstrained bars. For non-homogeneous materials or constrained structures, results may not be accurate. Always verify with material-specific data.

Tips & Common Mistakes

Tips

  • Use the material's average expansion coefficient over the temperature range for better accuracy.
  • Ensure the bar is free to expand (unconstrained) for the formula to apply.
  • Double-check that all units are consistent: meters, per Kelvin, and Kelvin.
  • For large temperature changes, consider that the coefficient may vary; use a value appropriate for the range.

Common Mistakes to Avoid

  • Using Celsius instead of Kelvin for temperature change – the change in Kelvin equals change in Celsius, but ensure you input the change, not absolute temperature.
  • Forgetting to convert length to meters if you have it in another unit.
  • Applying the calculator to constrained bars or non-homogeneous materials, which can lead to incorrect results.

Last updated: August 13, 2026