What is a regular octahedron?

A regular octahedron is one of the five Platonic solids. It has eight equilateral triangular faces, six vertices, and twelve edges, all of equal length.

What is the formula for the volume of a regular octahedron?

The volume is V = (√2 / 3) × a³, where a is the edge length. This simplifies to approximately V ≈ 0.4714 × a³.

Does this work for irregular octahedra?

No. This calculator is for regular octahedra only, where all edges are equal. Irregular octahedra require a different approach depending on their geometry.

What units can I use?

You can enter any positive number. The result is in the corresponding cubic unit — for example, entering millimeters gives cubic millimeters (mm³).

How precise is the calculation?

The calculation uses JavaScript's full double-precision floating-point arithmetic (64-bit), which gives about 15–17 significant decimal digits of accuracy.

Volume of a Octahedron Calculator

Calculate the volume of a regular octahedron from its edge length using V = (sqrt(2)/3) * a³.

Edge Length

Enter the length of one edge of the regular octahedron.

Edge Length (a)

Unit

Formula

V = (√2 / 3) × a³

≈ 0.47140452 × a³

Result

Enter an edge length and click Calculate.

Quick Examples

Summary

A regular octahedron is a Platonic solid with eight equilateral triangular faces, six vertices, and twelve edges of equal length. This calculator uses the exact formula V = (√2 / 3) × a³ to compute its volume instantly. Enter any positive edge length to see the volume in cubic units.

How it works

Enter the edge length of the regular octahedron.
Select the unit (mm, cm, m, in, ft) for your measurement.
The calculator applies the formula V = (√2 / 3) × a³.
Volume is displayed in both standard and scientific notation.
Use the Copy button to copy the result to your clipboard.

Use cases

Calculate material volume for 3D-printed octahedral models.
Solve geometry homework involving Platonic solids.
Estimate volume for crystal structures in chemistry.
Verify results for engineering and architecture projects.
Compare volumes of different octahedron sizes side by side.
Convert between unit systems with the built-in unit selector.

Frequently Asked Questions

Last updated: 2026-05-25 · Reviewed by Nham Vu