Thermal Expansion Calculator
Calculate how much a material expands or contracts with temperature change.
Covers metals, plastics, glass, and concrete with built-in coefficients.
What Is Thermal Expansion? Most materials expand when heated and contract when cooled. The amount of expansion is proportional to the temperature change and the original length. This is described by the coefficient of thermal expansion (CTE), symbolized as alpha.
The Formula Delta_L = alpha x L x Delta_T. Where Delta_L is the change in length, alpha is the coefficient of thermal expansion (per degree), L is the original length, and Delta_T is the temperature change. For volume expansion: Delta_V = 3 x alpha x V x Delta_T (for isotropic materials).
Common CTE Values (per degree C x 10^-6) Aluminum: 23.1. Copper: 16.5. Steel (carbon): 12.0. Stainless steel (304): 17.3. Brass: 19.0. Titanium: 8.6. Glass (borosilicate): 3.3. Concrete: 12.0. PVC plastic: 52.0. Wood (along grain): 3-5. Invar (nickel-iron alloy): 1.2 (designed for minimal expansion).
Why It Matters Bridges have expansion joints to accommodate thermal movement — a 100-meter steel bridge can expand by 14 cm between winter and summer. Railroad tracks can buckle in extreme heat if expansion joints fail. Pipelines, buildings, and spacecraft all require thermal expansion calculations. Bimetallic strips (two metals with different CTEs bonded together) are used in thermostats — the strip bends as temperature changes because one side expands more than the other.
Thermal Stress If a material is constrained (cannot expand freely), thermal expansion creates stress: sigma = alpha x E x Delta_T. Where E is the elastic modulus. This thermal stress can crack concrete, warp metal parts, and fracture glass. Pyrex (borosilicate glass) has a low CTE specifically to resist thermal shock in cooking and laboratory use.