Thermal Expansion Calculator
How much a part grows — or shrinks — for a given temperature change.
What is Thermal Expansion?
Almost everything expands when it warms, by about the same fraction per kelvin for a given material: 12 µm per metre per kelvin for steel, 23 for aluminium, 70 for PVC. The change looks small until a structure is long or the temperature swing is large — a 12 m steel member at 40 K above its installation temperature grows 5.8 mm, which is why bridge bearings slide, rails have gaps, and a long run of pipe needs an expansion loop.
How it works
The change in length is the linear coefficient times the original length times the temperature change, with ΔT allowed to be negative so cooling gives shrinkage. The coefficient is entered in µm/m·K (numerically the same as 10⁻⁶/K, which is how tables quote it) and can be picked from presets. The page reports the change in millimetres, the new length, and the strain in µm/m, and it is explicit that this is the *unrestrained* case: fixed at both ends, the same expansion becomes a stress of E·α·ΔT instead.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Realistic sample
Type or paste any realistic input — the tool computes the result locally and instantly.
Common mistakes
Expecting a server round-trip
Nothing is uploaded — every tool in this category runs entirely in your browser.