Area Thermal Expansion Calculator

How it is calculated

The change in area is ΔA = 2 × α × A × ΔT. A is the starting area in any unit you like (m², cm², ft²), and the answer comes out in that same unit. α is the linear expansion coefficient in parts per million per degree (ppm/°C); the tool multiplies it by 10⁻⁶. ΔT is the temperature change, final minus starting, in °C (a change of 1 K is the same size). A negative ΔT gives a shrinking area. The new area is A + ΔA. Both figures are shown to six decimals. Area and α must not be negative. This is the first-order formula, accurate for the small relative changes that solids normally show.

Common mistakes

• Entering the area coefficient instead of the linear one. The tool already doubles α, so typing 46 ppm/°C for aluminium would double-count and give twice the true change.
• Entering α as 0.000023 instead of 23. The field is in ppm/°C, so the small decimal form would be treated as almost zero expansion.
• Giving the final temperature instead of the change. A panel going from 20 °C to 80 °C needs ΔT = 60, not 80, and cooling needs a negative number.
• Using Fahrenheit differences. The coefficient is per °C, so a change of 108 °F must first be converted to 60 °C (a difference is multiplied by 5/9, with no 32 offset).
• Applying it to a plate with holes or cut-outs and assuming the hole grows less. The hole expands as if it were filled with the same material, so the whole outline scales by the same factor.