Thermal expansion calculator (linear and volume)
Choose the type, then enter the original length or volume, the coefficient and both temperatures to get the change and new value. Handy for engineers, students and pipe fitters.
Loading the tool…
Processing and privacy: The result is calculated inside your browser and your data is not sent to any server.
How to use it
- Enter expansion type, original length or volume, expansion coefficient (steel linear about 12), initial temperature and final temperature.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
Linear: ΔL = α × L₀ × ΔT. Volume: ΔV = β × V₀ × ΔT. The coefficient is entered in units of 10⁻⁶ per kelvin.
Example
Inputs: Expansion type = Linear (rod, pipe, rail), Original length or volume = 100, Expansion coefficient (steel linear about 12) = 12 × 10⁻⁶ /K, Initial temperature = 20 °C, Final temperature = 60 °C. Result: Change in length: 0.048 same unit as input; New value: 100.048; Percent change: 0.048%.
Limits and caveats
- It assumes a constant coefficient over the range; fine for metals in normal ranges but approximate for liquids such as water.
- Coefficients vary by alloy and grade, so use the manufacturer's value for engineering work.
Questions about this tool
What are linear coefficients for common materials?
Roughly, in 10⁻⁶ per kelvin: steel 12, copper 17, aluminum 23, ordinary glass 9 and PVC pipe about 50 to 80.
How do I get the volume coefficient of a solid?
For uniform materials it is about three times the linear value, so steel is about 36.
What is the volume coefficient of water?
About 207 × 10⁻⁶ per kelvin at 20 °C, rising as the water gets warmer.