Thermal Expansion Calculator
Calculate how much a material lengthens with temperature using its linear expansion coefficient.
How it works
ΔL = α × L₀ × ΔT · final length = L₀ + ΔL
Most solids expand slightly when heated. The linear expansion coefficient α gives the fractional change in length per degree Celsius — steel is about 0.000012 per °C. The length change equals α times the original length times the temperature change; positive means expansion, negative means contraction.
Worked example
A 10 m steel beam (α = 0.000012/°C) heated by 50 °C grows by ΔL = 0.000012 × 10 × 50 = 0.006 m, or 6 mm.
Frequently asked questions
Why do bridges have expansion joints?
Long spans lengthen noticeably on hot days. Expansion joints leave room for that growth so the structure does not buckle or crack under the stress.
Where do I find the coefficient α?
Materials tables list it. Typical values are around 0.000012/°C for steel, 0.000023/°C for aluminium and 0.000009/°C for glass.
Does this formula work for area or volume?
This is linear expansion. Area expansion uses roughly 2α and volume expansion roughly 3α for the same material and temperature change.
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