A regular octahedron has 8 equilateral triangle faces. Since one face has area rac{sqrt{3}}{4}a^2, multiplying by 8 gives $2sqrt{3}a^2$.

This is why the calculator only needs a single edge length.

Use this tool for geometry homework, surface-material estimates, or comparing Platonic solids.

The preview keeps the face structure visible so the number is tied to the solid instead of floating alone.